# -*- coding:utf-8 -*-
#
# Copyright (C) 2008 The Android Open Source Project
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

from __future__ import print_function
import errno
import filecmp
import glob
import json
import os
import random
import re
import shutil
import stat
import subprocess
import sys
import tarfile
import tempfile
import time
import traceback
import requests

from color import Coloring
from git_command import GitCommand, git_require
from git_config import GitConfig, IsId, GetSchemeFromUrl, GetUrlCookieFile, \
    ID_RE
from settings import GITCODE_SSH, GITCODE_USER_API,GITCODE_URL, TIMEOUT, GITCODE_PR_V3_API, GITCODE_PR_V5_API
from error import GitError, HookError, UploadError, DownloadError, PullRequestError, ForkProjectError
from error import ManifestInvalidRevisionError, ManifestInvalidPathError
from error import NoManifestException
import platform_utils
import progress
from repo_trace import IsTrace, Trace

from git_refs import GitRefs, HEAD, R_HEADS, R_TAGS, R_PUB, R_M, R_WORKTREE_M

from pyversion import is_python3
if is_python3():
    import urllib.parse
else:
    import imp
    import urlparse
    urllib = imp.new_module('urllib')
    urllib.parse = urlparse
    input = raw_input  # noqa: F821


# Maximum sleep time allowed during retries.
MAXIMUM_RETRY_SLEEP_SEC = 3600.0
# +-10% random jitter is added to each Fetches retry sleep duration.
RETRY_JITTER_PERCENT = 0.1


def _lwrite(path, content):
    lock = '%s.lock' % path

    with open(lock, 'w') as fd:
        fd.write(content)

    try:
        platform_utils.rename(lock, path)
    except OSError:
        platform_utils.remove(lock)
        raise


def _error(fmt, *args):
    msg = fmt % args
    print('error: %s' % msg, file=sys.stderr)


def _warn(fmt, *args):
    msg = fmt % args
    print('warn: %s' % msg, file=sys.stderr)


def not_rev(r):
    return '^' + r


def sq(r):
    return "'" + r.replace("'", "'\''") + "'"


_project_hook_list = None


def _ProjectHooks():
    """List the hooks present in the 'hooks' directory.

    These hooks are project hooks and are copied to the '.git/hooks' directory
    of all subprojects.

    This function caches the list of hooks (based on the contents of the
    'repo/hooks' directory) on the first call.

    Returns:
      A list of absolute paths to all of the files in the hooks directory.
    """
    global _project_hook_list
    if _project_hook_list is None:
        d = platform_utils.realpath(os.path.abspath(os.path.dirname(__file__)))
        d = os.path.join(d, 'hooks')
        _project_hook_list = [os.path.join(d, x) for x in platform_utils.listdir(d)]
    return _project_hook_list


class DownloadedChange(object):
    _commit_cache = None

    def __init__(self, project, base, change_id, ps_id, commit):
        self.project = project
        self.base = base
        self.change_id = change_id
        self.ps_id = ps_id
        self.commit = commit

    @property
    def commits(self):
        if self._commit_cache is None:
            self._commit_cache = self.project.bare_git.rev_list('--abbrev=8',
                                                                '--abbrev-commit',
                                                                '--pretty=oneline',
                                                                '--reverse',
                                                                '--date-order',
                                                                not_rev(self.base),
                                                                self.commit,
                                                                '--')
        return self._commit_cache


class ReviewableBranch(object):
    _commit_cache = None
    _base_exists = None

    def __init__(self, project, branch, base):
        self.project = project
        self.branch = branch
        self.base = base

    @property
    def name(self):
        return self.branch.name

    @property
    def commits(self):
        if self._commit_cache is None:
            args = ('--abbrev=8', '--abbrev-commit', '--pretty=oneline', '--reverse',
                    '--date-order', not_rev(self.base), R_HEADS + self.name, '--')
            try:
                self._commit_cache = self.project.bare_git.rev_list(*args)
            except GitError:
                # We weren't able to probe the commits for this branch.  Was it tracking
                # a branch that no longer exists?  If so, return no commits.  Otherwise,
                # rethrow the error as we don't know what's going on.
                if self.base_exists:
                    raise

                self._commit_cache = []

        return self._commit_cache

    @property
    def unabbrev_commits(self):
        r = dict()
        for commit in self.project.bare_git.rev_list(not_rev(self.base),
                                                     R_HEADS + self.name,
                                                     '--'):
            r[commit[0:8]] = commit
        return r

    @property
    def date(self):
        return self.project.bare_git.log('--pretty=format:%cd',
                                         '-n', '1',
                                         R_HEADS + self.name,
                                         '--')

    @property
    def base_exists(self):
        """Whether the branch we're tracking exists.

        Normally it should, but sometimes branches we track can get deleted.
        """
        if self._base_exists is None:
            try:
                self.project.bare_git.rev_parse('--verify', not_rev(self.base))
                # If we're still here, the base branch exists.
                self._base_exists = True
            except GitError:
                # If we failed to verify, the base branch doesn't exist.
                self._base_exists = False

        return self._base_exists

    def UploadForReview(self, people,
                        dryrun=False,
                        auto_topic=False,
                        hashtags=(),
                        labels=(),
                        private=False,
                        notify=None,
                        wip=False,
                        dest_branch=None,
                        validate_certs=True,
                        push_options=None):
        self.project.UploadForReview(branch=self.name,
                                     people=people,
                                     dryrun=dryrun,
                                     auto_topic=auto_topic,
                                     hashtags=hashtags,
                                     labels=labels,
                                     private=private,
                                     notify=notify,
                                     wip=wip,
                                     dest_branch=dest_branch,
                                     validate_certs=validate_certs,
                                     push_options=push_options)

    def GetPublishedRefs(self):
        refs = {}
        output = self.project.bare_git.ls_remote(
            self.branch.remote.SshReviewUrl(self.project.UserEmail),
            'refs/changes/*')
        for line in output.split('\n'):
            try:
                (sha, ref) = line.split()
                refs[sha] = ref
            except ValueError:
                pass

        return refs


class StatusColoring(Coloring):

    def __init__(self, config):
        Coloring.__init__(self, config, 'status')
        self.project = self.printer('header', attr='bold')
        self.branch = self.printer('header', attr='bold')
        self.nobranch = self.printer('nobranch', fg='red')
        self.important = self.printer('important', fg='red')

        self.added = self.printer('added', fg='green')
        self.changed = self.printer('changed', fg='red')
        self.untracked = self.printer('untracked', fg='red')


class DiffColoring(Coloring):

    def __init__(self, config):
        Coloring.__init__(self, config, 'diff')
        self.project = self.printer('header', attr='bold')
        self.fail = self.printer('fail', fg='red')


class _Annotation(object):

    def __init__(self, name, value, keep):
        self.name = name
        self.value = value
        self.keep = keep


def _SafeExpandPath(base, subpath, skipfinal=False):
    """Make sure |subpath| is completely safe under |base|.

    We make sure no intermediate symlinks are traversed, and that the final path
    is not a special file (e.g. not a socket or fifo).

    NB: We rely on a number of paths already being filtered out while parsing the
    manifest.  See the validation logic in manifest_xml.py for more details.
    """
    # Split up the path by its components.  We can't use os.path.sep exclusively
    # as some platforms (like Windows) will convert / to \ and that bypasses all
    # our constructed logic here.  Especially since manifest authors only use
    # / in their paths.
    resep = re.compile(r'[/%s]' % re.escape(os.path.sep))
    components = resep.split(subpath)
    if skipfinal:
        # Whether the caller handles the final component itself.
        finalpart = components.pop()

    path = base
    for part in components:
        if part in {'.', '..'}:
            raise ManifestInvalidPathError(
                '%s: "%s" not allowed in paths' % (subpath, part))

        path = os.path.join(path, part)
        if platform_utils.islink(path):
            raise ManifestInvalidPathError(
                '%s: traversing symlinks not allow' % (path,))

        if os.path.exists(path):
            if not os.path.isfile(path) and not platform_utils.isdir(path):
                raise ManifestInvalidPathError(
                    '%s: only regular files & directories allowed' % (path,))

    if skipfinal:
        path = os.path.join(path, finalpart)

    return path


class _CopyFile(object):
    """Container for <copyfile> manifest element."""

    def __init__(self, git_worktree, src, topdir, dest):
        """Register a <copyfile> request.

        Args:
          git_worktree: Absolute path to the git project checkout.
          src: Relative path under |git_worktree| of file to read.
          topdir: Absolute path to the top of the repo client checkout.
          dest: Relative path under |topdir| of file to write.
        """
        self.git_worktree = git_worktree
        self.topdir = topdir
        self.src = src
        self.dest = dest

    def _Copy(self):
        src = _SafeExpandPath(self.git_worktree, self.src)
        dest = _SafeExpandPath(self.topdir, self.dest)

        if platform_utils.isdir(src):
            raise ManifestInvalidPathError(
                '%s: copying from directory not supported' % (self.src,))
        if platform_utils.isdir(dest):
            raise ManifestInvalidPathError(
                '%s: copying to directory not allowed' % (self.dest,))

        # copy file if it does not exist or is out of date
        if not os.path.exists(dest) or not filecmp.cmp(src, dest):
            try:
                # remove existing file first, since it might be read-only
                if os.path.exists(dest):
                    platform_utils.remove(dest)
                else:
                    dest_dir = os.path.dirname(dest)
                    if not platform_utils.isdir(dest_dir):
                        os.makedirs(dest_dir)
                shutil.copy(src, dest)
                # make the file read-only
                mode = os.stat(dest)[stat.ST_MODE]
                mode = mode & ~(stat.S_IWUSR | stat.S_IWGRP | stat.S_IWOTH)
                os.chmod(dest, mode)
            except IOError:
                _error('Cannot copy file %s to %s', src, dest)


class _LinkFile(object):
    """Container for <linkfile> manifest element."""

    def __init__(self, git_worktree, src, topdir, dest):
        """Register a <linkfile> request.

        Args:
          git_worktree: Absolute path to the git project checkout.
          src: Target of symlink relative to path under |git_worktree|.
          topdir: Absolute path to the top of the repo client checkout.
          dest: Relative path under |topdir| of symlink to create.
        """
        self.git_worktree = git_worktree
        self.topdir = topdir
        self.src = src
        self.dest = dest

    def __linkIt(self, relSrc, absDest):
        # link file if it does not exist or is out of date
        if not platform_utils.islink(absDest) or (platform_utils.readlink(absDest) != relSrc):
            try:
                # remove existing file first, since it might be read-only
                if os.path.lexists(absDest):
                    platform_utils.remove(absDest)
                else:
                    dest_dir = os.path.dirname(absDest)
                    if not platform_utils.isdir(dest_dir):
                        os.makedirs(dest_dir)
                platform_utils.symlink(relSrc, absDest)
            except IOError:
                _error('Cannot link file %s to %s', relSrc, absDest)

    def _Link(self):
        """Link the self.src & self.dest paths.

        Handles wild cards on the src linking all of the files in the source in to
        the destination directory.
        """
        # Some people use src="." to create stable links to projects.  Lets allow
        # that but reject all other uses of "." to keep things simple.
        if self.src == '.':
            src = self.git_worktree
        else:
            src = _SafeExpandPath(self.git_worktree, self.src)

        if not glob.has_magic(src):
            # Entity does not contain a wild card so just a simple one to one link operation.
            dest = _SafeExpandPath(self.topdir, self.dest, skipfinal=True)
            # dest & src are absolute paths at this point.  Make sure the target of
            # the symlink is relative in the context of the repo client checkout.
            relpath = os.path.relpath(src, os.path.dirname(dest))
            self.__linkIt(relpath, dest)
        else:
            dest = _SafeExpandPath(self.topdir, self.dest)
            # Entity contains a wild card.
            if os.path.exists(dest) and not platform_utils.isdir(dest):
                _error('Link error: src with wildcard, %s must be a directory', dest)
            else:
                for absSrcFile in glob.glob(src):
                    # Create a releative path from source dir to destination dir
                    absSrcDir = os.path.dirname(absSrcFile)
                    relSrcDir = os.path.relpath(absSrcDir, dest)

                    # Get the source file name
                    srcFile = os.path.basename(absSrcFile)

                    # Now form the final full paths to srcFile. They will be
                    # absolute for the desintaiton and relative for the srouce.
                    absDest = os.path.join(dest, srcFile)
                    relSrc = os.path.join(relSrcDir, srcFile)
                    self.__linkIt(relSrc, absDest)


class RemoteSpec(object):

    def __init__(self,
                 name,
                 url=None,
                 pushUrl=None,
                 review=None,
                 revision=None,
                 orig_name=None,
                 fetchUrl=None):
        self.name = name
        self.url = url
        self.pushUrl = pushUrl
        self.review = review
        self.revision = revision
        self.orig_name = orig_name
        self.fetchUrl = fetchUrl


class RepoHook(object):

    """A RepoHook contains information about a script to run as a hook.

    Hooks are used to run a python script before running an upload (for instance,
    to run presubmit checks).  Eventually, we may have hooks for other actions.

    This shouldn't be confused with files in the 'repo/hooks' directory.  Those
    files are copied into each '.git/hooks' folder for each project.  Repo-level
    hooks are associated instead with repo actions.

    Hooks are always python.  When a hook is run, we will load the hook into the
    interpreter and execute its main() function.
    """

    def __init__(self,
                 hook_type,
                 hooks_project,
                 topdir,
                 manifest_url,
                 abort_if_user_denies=False):
        """RepoHook constructor.

        Params:
          hook_type: A string representing the type of hook.  This is also used
              to figure out the name of the file containing the hook.  For
              example: 'pre-upload'.
          hooks_project: The project containing the repo hooks.  If you have a
              manifest, this is manifest.repo_hooks_project.  OK if this is None,
              which will make the hook a no-op.
          topdir: Repo's top directory (the one containing the .repo directory).
              Scripts will run with CWD as this directory.  If you have a manifest,
              this is manifest.topdir
          manifest_url: The URL to the manifest git repo.
          abort_if_user_denies: If True, we'll throw a HookError() if the user
              doesn't allow us to run the hook.
        """
        self._hook_type = hook_type
        self._hooks_project = hooks_project
        self._manifest_url = manifest_url
        self._topdir = topdir
        self._abort_if_user_denies = abort_if_user_denies

        # Store the full path to the script for convenience.
        if self._hooks_project:
            self._script_fullpath = os.path.join(self._hooks_project.worktree,
                                                 self._hook_type + '.py')
        else:
            self._script_fullpath = None

    def _GetHash(self):
        """Return a hash of the contents of the hooks directory.

        We'll just use git to do this.  This hash has the property that if anything
        changes in the directory we will return a different has.

        SECURITY CONSIDERATION:
          This hash only represents the contents of files in the hook directory, not
          any other files imported or called by hooks.  Changes to imported files
          can change the script behavior without affecting the hash.

        Returns:
          A string representing the hash.  This will always be ASCII so that it can
          be printed to the user easily.
        """
        assert self._hooks_project, "Must have hooks to calculate their hash."

        # We will use the work_git object rather than just calling GetRevisionId().
        # That gives us a hash of the latest checked in version of the files that
        # the user will actually be executing.  Specifically, GetRevisionId()
        # doesn't appear to change even if a user checks out a different version
        # of the hooks repo (via git checkout) nor if a user commits their own revs.
        #
        # NOTE: Local (non-committed) changes will not be factored into this hash.
        # I think this is OK, since we're really only worried about warning the user
        # about upstream changes.
        return self._hooks_project.work_git.rev_parse('HEAD')

    def _GetMustVerb(self):
        """Return 'must' if the hook is required; 'should' if not."""
        if self._abort_if_user_denies:
            return 'must'
        else:
            return 'should'

    def _CheckForHookApproval(self):
        """Check to see whether this hook has been approved.

        We'll accept approval of manifest URLs if they're using secure transports.
        This way the user can say they trust the manifest hoster.  For insecure
        hosts, we fall back to checking the hash of the hooks repo.

        Note that we ask permission for each individual hook even though we use
        the hash of all hooks when detecting changes.  We'd like the user to be
        able to approve / deny each hook individually.  We only use the hash of all
        hooks because there is no other easy way to detect changes to local imports.

        Returns:
          True if this hook is approved to run; False otherwise.

        Raises:
          HookError: Raised if the user doesn't approve and abort_if_user_denies
              was passed to the consturctor.
        """
        if self._ManifestUrlHasSecureScheme():
            return self._CheckForHookApprovalManifest()
        else:
            return self._CheckForHookApprovalHash()

    def _CheckForHookApprovalHelper(self, subkey, new_val, main_prompt,
                                    changed_prompt):
        """Check for approval for a particular attribute and hook.

        Args:
          subkey: The git config key under [repo.hooks.<hook_type>] to store the
              last approved string.
          new_val: The new value to compare against the last approved one.
          main_prompt: Message to display to the user to ask for approval.
          changed_prompt: Message explaining why we're re-asking for approval.

        Returns:
          True if this hook is approved to run; False otherwise.

        Raises:
          HookError: Raised if the user doesn't approve and abort_if_user_denies
              was passed to the consturctor.
        """
        hooks_config = self._hooks_project.config
        git_approval_key = 'repo.hooks.%s.%s' % (self._hook_type, subkey)

        # Get the last value that the user approved for this hook; may be None.
        old_val = hooks_config.GetString(git_approval_key)

        if old_val is not None:
            # User previously approved hook and asked not to be prompted again.
            if new_val == old_val:
                # Approval matched.  We're done.
                return True
            else:
                # Give the user a reason why we're prompting, since they last told
                # us to "never ask again".
                prompt = 'WARNING: %s\n\n' % (changed_prompt,)
        else:
            prompt = ''

        # Prompt the user if we're not on a tty; on a tty we'll assume "no".
        if sys.stdout.isatty():
            prompt += main_prompt + ' (yes/always/NO)? '
            response = input(prompt).lower()
            print()

            # User is doing a one-time approval.
            if response in ('y', 'yes'):
                return True
            elif response == 'always':
                hooks_config.SetString(git_approval_key, new_val)
                return True

        # For anything else, we'll assume no approval.
        if self._abort_if_user_denies:
            raise HookError('You must allow the %s hook or use --no-verify.' %
                            self._hook_type)

        return False

    def _ManifestUrlHasSecureScheme(self):
        """Check if the URI for the manifest is a secure transport."""
        secure_schemes = ('file', 'https', 'ssh', 'persistent-https', 'sso', 'rpc')
        parse_results = urllib.parse.urlparse(self._manifest_url)
        return parse_results.scheme in secure_schemes

    def _CheckForHookApprovalManifest(self):
        """Check whether the user has approved this manifest host.

        Returns:
          True if this hook is approved to run; False otherwise.
        """
        return self._CheckForHookApprovalHelper(
            'approvedmanifest',
            self._manifest_url,
            'Run hook scripts from %s' % (self._manifest_url,),
            'Manifest URL has changed since %s was allowed.' % (self._hook_type,))

    def _CheckForHookApprovalHash(self):
        """Check whether the user has approved the hooks repo.

        Returns:
          True if this hook is approved to run; False otherwise.
        """
        prompt = ('Repo %s run the script:\n'
                  '  %s\n'
                  '\n'
                  'Do you want to allow this script to run')
        return self._CheckForHookApprovalHelper(
            'approvedhash',
            self._GetHash(),
            prompt % (self._GetMustVerb(), self._script_fullpath),
            'Scripts have changed since %s was allowed.' % (self._hook_type,))

    @staticmethod
    def _ExtractInterpFromShebang(data):
        """Extract the interpreter used in the shebang.

        Try to locate the interpreter the script is using (ignoring `env`).

        Args:
          data: The file content of the script.

        Returns:
          The basename of the main script interpreter, or None if a shebang is not
          used or could not be parsed out.
        """
        firstline = data.splitlines()[:1]
        if not firstline:
            return None

        # The format here can be tricky.
        shebang = firstline[0].strip()
        m = re.match(r'^#!\s*([^\s]+)(?:\s+([^\s]+))?', shebang)
        if not m:
            return None

        # If the using `env`, find the target program.
        interp = m.group(1)
        if os.path.basename(interp) == 'env':
            interp = m.group(2)

        return interp

    def _ExecuteHookViaReexec(self, interp, context, **kwargs):
        """Execute the hook script through |interp|.

        Note: Support for this feature should be dropped ~Jun 2021.

        Args:
          interp: The Python program to run.
          context: Basic Python context to execute the hook inside.
          kwargs: Arbitrary arguments to pass to the hook script.

        Raises:
          HookError: When the hooks failed for any reason.
        """
        # This logic needs to be kept in sync with _ExecuteHookViaImport below.
        script = """
import json, os, sys
path = '''%(path)s'''
kwargs = json.loads('''%(kwargs)s''')
context = json.loads('''%(context)s''')
sys.path.insert(0, os.path.dirname(path))
data = open(path).read()
exec(compile(data, path, 'exec'), context)
context['main'](**kwargs)
""" % {
            'path': self._script_fullpath,
            'kwargs': json.dumps(kwargs),
            'context': json.dumps(context),
        }

        # We pass the script via stdin to avoid OS argv limits.  It also makes
        # unhandled exception tracebacks less verbose/confusing for users.
        cmd = [interp, '-c', 'import sys; exec(sys.stdin.read())']
        proc = subprocess.Popen(cmd, stdin=subprocess.PIPE)
        proc.communicate(input=script.encode('utf-8'))
        if proc.returncode:
            raise HookError('Failed to run %s hook.' % (self._hook_type,))

    def _ExecuteHookViaImport(self, data, context, **kwargs):
        """Execute the hook code in |data| directly.

        Args:
          data: The code of the hook to execute.
          context: Basic Python context to execute the hook inside.
          kwargs: Arbitrary arguments to pass to the hook script.

        Raises:
          HookError: When the hooks failed for any reason.
        """
        # Exec, storing global context in the context dict.  We catch exceptions
        # and convert to a HookError w/ just the failing traceback.
        try:
            exec(compile(data, self._script_fullpath, 'exec'), context)
        except Exception:
            raise HookError('%s\nFailed to import %s hook; see traceback above.' %
                            (traceback.format_exc(), self._hook_type))

        # Running the script should have defined a main() function.
        if 'main' not in context:
            raise HookError('Missing main() in: "%s"' % self._script_fullpath)

        # Call the main function in the hook.  If the hook should cause the
        # build to fail, it will raise an Exception.  We'll catch that convert
        # to a HookError w/ just the failing traceback.
        try:
            context['main'](**kwargs)
        except Exception:
            raise HookError('%s\nFailed to run main() for %s hook; see traceback '
                            'above.' % (traceback.format_exc(), self._hook_type))

    def _ExecuteHook(self, **kwargs):
        """Actually execute the given hook.

        This will run the hook's 'main' function in our python interpreter.

        Args:
          kwargs: Keyword arguments to pass to the hook.  These are often specific
              to the hook type.  For instance, pre-upload hooks will contain
              a project_list.
        """
        # Keep sys.path and CWD stashed away so that we can always restore them
        # upon function exit.
        orig_path = os.getcwd()
        orig_syspath = sys.path

        print("\nStartExecuteHook: %s" % self._script_fullpath, file=sys.stdout)

        try:
            # Always run hooks with CWD as topdir.
            os.chdir(self._topdir)

            # Put the hook dir as the first item of sys.path so hooks can do
            # relative imports.  We want to replace the repo dir as [0] so
            # hooks can't import repo files.
            sys.path = [os.path.dirname(self._script_fullpath)] + sys.path[1:]

            # Initial global context for the hook to run within.
            context = {'__file__': self._script_fullpath}

            # Add 'hook_should_take_kwargs' to the arguments to be passed to main.
            # We don't actually want hooks to define their main with this argument--
            # it's there to remind them that their hook should always take **kwargs.
            # For instance, a pre-upload hook should be defined like:
            #   def main(project_list, **kwargs):
            #
            # This allows us to later expand the API without breaking old hooks.
            kwargs = kwargs.copy()
            kwargs['hook_should_take_kwargs'] = True

            # See what version of python the hook has been written against.
            data = open(self._script_fullpath).read()
            interp = self._ExtractInterpFromShebang(data)
            reexec = False
            if interp:
                prog = os.path.basename(interp)
                if prog.startswith('python2') and sys.version_info.major != 2:
                    reexec = True
                elif prog.startswith('python3') and sys.version_info.major == 2:
                    reexec = True

            # Attempt to execute the hooks through the requested version of Python.
            if reexec:
                try:
                    self._ExecuteHookViaReexec(interp, context, **kwargs)
                except OSError as e:
                    if e.errno == errno.ENOENT:
                        # We couldn't find the interpreter, so fallback to importing.
                        reexec = False
                    else:
                        raise

            # Run the hook by importing directly.
            if not reexec:
                self._ExecuteHookViaImport(data, context, **kwargs)
        finally:
            # Restore sys.path and CWD.
            sys.path = orig_syspath
            os.chdir(orig_path)

    def Run(self, user_allows_all_hooks, **kwargs):
        """Run the hook.

        If the hook doesn't exist (because there is no hooks project or because
        this particular hook is not enabled), this is a no-op.

        Args:
          user_allows_all_hooks: If True, we will never prompt about running the
              hook--we'll just assume it's OK to run it.
          kwargs: Keyword arguments to pass to the hook.  These are often specific
              to the hook type.  For instance, pre-upload hooks will contain
              a project_list.

        Raises:
          HookError: If there was a problem finding the hook or the user declined
              to run a required hook (from _CheckForHookApproval).
        """
        # No-op if there is no hooks project or if hook is disabled.
        if ((not self._hooks_project) or (self._hook_type not in
                                          self._hooks_project.enabled_repo_hooks)):
            return

        # Bail with a nice error if we can't find the hook.
        if not os.path.isfile(self._script_fullpath):
            raise HookError('Couldn\'t find repo hook: "%s"' % self._script_fullpath)

        # Make sure the user is OK with running the hook.
        if (not user_allows_all_hooks) and (not self._CheckForHookApproval()):
            return

        # Run the hook with the same version of python we're using.
        self._ExecuteHook(**kwargs)


class Project(object):
    # These objects can be shared between several working trees.
    shareable_files = ['description', 'info']
    shareable_dirs = ['hooks', 'objects', 'rr-cache', 'svn']
    # These objects can only be used by a single working tree.
    working_tree_files = ['config', 'packed-refs', 'shallow']
    working_tree_dirs = ['logs', 'refs']

    def __init__(self,
                 manifest,
                 name,
                 remote,
                 gitdir,
                 objdir,
                 worktree,
                 relpath,
                 revisionExpr,
                 revisionId,
                 rebase=True,
                 groups=None,
                 sync_c=False,
                 sync_s=False,
                 sync_tags=True,
                 clone_depth=None,
                 upstream=None,
                 parent=None,
                 use_git_worktrees=False,
                 is_derived=False,
                 dest_branch=None,
                 optimized_fetch=False,
                 retry_fetches=0,
                 old_revision=None):
        """Init a Project object.

        Args:
          manifest: The XmlManifest object.
          name: The `name` attribute of manifest.xml's project element.
          remote: RemoteSpec object specifying its remote's properties.
          gitdir: Absolute path of git directory.
          objdir: Absolute path of directory to store git objects.
          worktree: Absolute path of git working tree.
          relpath: Relative path of git working tree to repo's top directory.
          revisionExpr: The `revision` attribute of manifest.xml's project element.
          revisionId: git commit id for checking out.
          rebase: The `rebase` attribute of manifest.xml's project element.
          groups: The `groups` attribute of manifest.xml's project element.
          sync_c: The `sync-c` attribute of manifest.xml's project element.
          sync_s: The `sync-s` attribute of manifest.xml's project element.
          sync_tags: The `sync-tags` attribute of manifest.xml's project element.
          upstream: The `upstream` attribute of manifest.xml's project element.
          parent: The parent Project object.
          use_git_worktrees: Whether to use `git worktree` for this project.
          is_derived: False if the project was explicitly defined in the manifest;
                      True if the project is a discovered submodule.
          dest_branch: The branch to which to push changes for review by default.
          optimized_fetch: If True, when a project is set to a sha1 revision, only
                           fetch from the remote if the sha1 is not present locally.
          retry_fetches: Retry remote fetches n times upon receiving transient error
                         with exponential backoff and jitter.
          old_revision: saved git commit id for open GITC projects.
        """
        self.manifest = manifest
        self.name = name
        self.remote = remote
        self.gitdir = gitdir.replace('\\', '/')
        self.objdir = objdir.replace('\\', '/')
        if worktree:
            self.worktree = os.path.normpath(worktree).replace('\\', '/')
        else:
            self.worktree = None
        self.relpath = relpath
        self.revisionExpr = revisionExpr

        if revisionId is None \
                and revisionExpr \
                and IsId(revisionExpr):
            self.revisionId = revisionExpr
        else:
            self.revisionId = revisionId

        self.rebase = rebase
        self.groups = groups
        self.sync_c = sync_c
        self.sync_s = sync_s
        self.sync_tags = sync_tags
        self.clone_depth = clone_depth
        self.upstream = upstream
        self.parent = parent
        # NB: Do not use this setting in __init__ to change behavior so that the
        # manifest.git checkout can inspect & change it after instantiating.  See
        # the XmlManifest init code for more info.
        self.use_git_worktrees = use_git_worktrees
        self.is_derived = is_derived
        self.optimized_fetch = optimized_fetch
        self.retry_fetches = max(0, retry_fetches)
        self.subprojects = []

        self.snapshots = {}
        self.copyfiles = []
        self.linkfiles = []
        self.annotations = []
        self.config = GitConfig.ForRepository(gitdir=self.gitdir,
                                              defaults=self.manifest.globalConfig)

        if self.worktree:
            self.work_git = self._GitGetByExec(self, bare=False, gitdir=gitdir)
        else:
            self.work_git = None
        self.bare_git = self._GitGetByExec(self, bare=True, gitdir=gitdir)
        self.bare_ref = GitRefs(gitdir)
        self.bare_objdir = self._GitGetByExec(self, bare=True, gitdir=objdir)
        self.dest_branch = dest_branch
        self.old_revision = old_revision

        # This will be filled in if a project is later identified to be the
        # project containing repo hooks.
        self.enabled_repo_hooks = []

    @property
    def Derived(self):
        return self.is_derived

    @property
    def Exists(self):
        return platform_utils.isdir(self.gitdir) and platform_utils.isdir(self.objdir)

    @property
    def CurrentBranch(self):
        """Obtain the name of the currently checked out branch.

        The branch name omits the 'refs/heads/' prefix.
        None is returned if the project is on a detached HEAD, or if the work_git is
        otheriwse inaccessible (e.g. an incomplete sync).
        """
        try:
            b = self.work_git.GetHead()
        except NoManifestException:
            # If the local checkout is in a bad state, don't barf.  Let the callers
            # process this like the head is unreadable.
            return None
        if b.startswith(R_HEADS):
            return b[len(R_HEADS):]
        return None

    def IsRebaseInProgress(self):
        return (os.path.exists(self.work_git.GetDotgitPath('rebase-apply')) or
                os.path.exists(self.work_git.GetDotgitPath('rebase-merge')) or
                os.path.exists(os.path.join(self.worktree, '.dotest')))

    def IsDirty(self, consider_untracked=True):
        """Is the working directory modified in some way?
        """
        self.work_git.update_index('-q',
                                   '--unmerged',
                                   '--ignore-missing',
                                   '--refresh')
        if self.work_git.DiffZ('diff-index', '-M', '--cached', HEAD):
            return True
        if self.work_git.DiffZ('diff-files'):
            return True
        if consider_untracked and self.work_git.LsOthers():
            return True
        return False

    _userident_name = None
    _userident_email = None

    @property
    def UserName(self):
        """Obtain the user's personal name.
        """
        if self._userident_name is None:
            self._LoadUserIdentity()
        return self._userident_name

    @property
    def UserEmail(self):
        """Obtain the user's email address.  This is very likely
           to be their Gerrit login.
        """
        if self._userident_email is None:
            self._LoadUserIdentity()
        return self._userident_email

    def _LoadUserIdentity(self):
        u = self.bare_git.var('GIT_COMMITTER_IDENT')
        m = re.compile("^(.*) <([^>]*)> ").match(u)
        if m:
            self._userident_name = m.group(1)
            self._userident_email = m.group(2)
        else:
            self._userident_name = ''
            self._userident_email = ''

    def GetRemote(self, name):
        """Get the configuration for a single remote.
        """
        return self.config.GetRemote(name)

    def GetBranch(self, name):
        """Get the configuration for a single branch.
        """
        return self.config.GetBranch(name)

    def GetBranches(self):
        """Get all existing local branches.
        """
        current = self.CurrentBranch
        all_refs = self._allrefs
        heads = {}

        for name, ref_id in all_refs.items():
            if name.startswith(R_HEADS):
                name = name[len(R_HEADS):]
                b = self.GetBranch(name)
                b.current = name == current
                b.published = None
                b.revision = ref_id
                heads[name] = b

        for name, ref_id in all_refs.items():
            if name.startswith(R_PUB):
                name = name[len(R_PUB):]
                b = heads.get(name)
                if b:
                    b.published = ref_id

        return heads

    def MatchesGroups(self, manifest_groups):
        """Returns true if the manifest groups specified at init should cause
           this project to be synced.
           Prefixing a manifest group with "-" inverts the meaning of a group.
           All projects are implicitly labelled with "all".

           labels are resolved in order.  In the example case of
           project_groups: "all,group1,group2"
           manifest_groups: "-group1,group2"
           the project will be matched.

           The special manifest group "default" will match any project that
           does not have the special project group "notdefault"
        """
        expanded_manifest_groups = manifest_groups or ['default']
        expanded_project_groups = ['all'] + (self.groups or [])
        if 'notdefault' not in expanded_project_groups:
            expanded_project_groups += ['default']

        matched = False
        for group in expanded_manifest_groups:
            if group.startswith('-') and group[1:] in expanded_project_groups:
                matched = False
            elif group in expanded_project_groups:
                matched = True

        return matched

    # Status Display ##
    def UncommitedFiles(self, get_all=True):
        """Returns a list of strings, uncommitted files in the git tree.

        Args:
          get_all: a boolean, if True - get information about all different
                   uncommitted files. If False - return as soon as any kind of
                   uncommitted files is detected.
        """
        details = []
        self.work_git.update_index('-q',
                                   '--unmerged',
                                   '--ignore-missing',
                                   '--refresh')
        if self.IsRebaseInProgress():
            details.append("rebase in progress")
            if not get_all:
                return details

        changes = self.work_git.DiffZ('diff-index', '--cached', HEAD).keys()
        if changes:
            details.extend(changes)
            if not get_all:
                return details

        changes = self.work_git.DiffZ('diff-files').keys()
        if changes:
            details.extend(changes)
            if not get_all:
                return details

        changes = self.work_git.LsOthers()
        if changes:
            details.extend(changes)

        return details

    def HasChanges(self):
        """Returns true if there are uncommitted changes.
        """
        if self.UncommitedFiles(get_all=False):
            return True
        else:
            return False

    def PrintWorkTreeStatus(self, output_redir=None, quiet=False):
        """Prints the status of the repository to stdout.

        Args:
          output_redir: If specified, redirect the output to this object.
          quiet:  If True then only print the project name.  Do not print
                  the modified files, branch name, etc.
        """
        if not platform_utils.isdir(self.worktree):
            if output_redir is None:
                output_redir = sys.stdout
            print(file=output_redir)
            print('project %s/' % self.relpath, file=output_redir)
            print('  missing (run "repo sync")', file=output_redir)
            return

        self.work_git.update_index('-q',
                                   '--unmerged',
                                   '--ignore-missing',
                                   '--refresh')
        rb = self.IsRebaseInProgress()
        di = self.work_git.DiffZ('diff-index', '-M', '--cached', HEAD)
        df = self.work_git.DiffZ('diff-files')
        do = self.work_git.LsOthers()
        if not rb and not di and not df and not do and not self.CurrentBranch:
            return 'CLEAN'

        out = StatusColoring(self.config)
        if output_redir is not None:
            out.redirect(output_redir)
        out.project('project %-40s', self.relpath + '/ ')

        if quiet:
            out.nl()
            return 'DIRTY'

        branch = self.CurrentBranch
        if branch is None:
            out.nobranch('(*** NO BRANCH ***)')
        else:
            out.branch('branch %s', branch)
        out.nl()

        if rb:
            out.important('prior sync failed; rebase still in progress')
            out.nl()

        paths = list()
        paths.extend(di.keys())
        paths.extend(df.keys())
        paths.extend(do)

        for p in sorted(set(paths)):
            try:
                i = di[p]
            except KeyError:
                i = None

            try:
                f = df[p]
            except KeyError:
                f = None

            if i:
                i_status = i.status.upper()
            else:
                i_status = '-'

            if f:
                f_status = f.status.lower()
            else:
                f_status = '-'

            if i and i.src_path:
                line = ' %s%s\t%s => %s (%s%%)' % (i_status, f_status,
                                                   i.src_path, p, i.level)
            else:
                line = ' %s%s\t%s' % (i_status, f_status, p)

            if i and not f:
                out.added('%s', line)
            elif (i and f) or (not i and f):
                out.changed('%s', line)
            elif not i and not f:
                out.untracked('%s', line)
            else:
                out.write('%s', line)
            out.nl()

        return 'DIRTY'

    def PrintWorkTreeDiff(self, absolute_paths=False):
        """Prints the status of the repository to stdout.
        """
        out = DiffColoring(self.config)
        cmd = ['diff']
        if out.is_on:
            cmd.append('--color')
        cmd.append(HEAD)
        if absolute_paths:
            cmd.append('--src-prefix=a/%s/' % self.relpath)
            cmd.append('--dst-prefix=b/%s/' % self.relpath)
        cmd.append('--')
        try:
            p = GitCommand(self,
                           cmd,
                           capture_stdout=True,
                           capture_stderr=True)
        except GitError as e:
            out.nl()
            out.project('project %s/' % self.relpath)
            out.nl()
            out.fail('%s', str(e))
            out.nl()
            return False
        has_diff = False
        for line in p.process.stdout:
            if not hasattr(line, 'encode'):
                line = line.decode()
            if not has_diff:
                out.nl()
                out.project('project %s/' % self.relpath)
                out.nl()
                has_diff = True
            print(line[:-1])
        return p.Wait() == 0

    # Publish / Upload ##
    def WasPublished(self, branch, all_refs=None):
        """Was the branch published (uploaded) for code review?
           If so, returns the SHA-1 hash of the last published
           state for the branch.
        """
        key = R_PUB + branch
        if all_refs is None:
            try:
                return self.bare_git.rev_parse(key)
            except GitError:
                return None
        else:
            try:
                return all_refs[key]
            except KeyError:
                return None

    def CleanPublishedCache(self, all_refs=None):
        """Prunes any stale published refs.
        """
        if all_refs is None:
            all_refs = self._allrefs
        heads = set()
        canrm = {}
        for name, ref_id in all_refs.items():
            if name.startswith(R_HEADS):
                heads.add(name)
            elif name.startswith(R_PUB):
                canrm[name] = ref_id

        for name, ref_id in canrm.items():
            n = name[len(R_PUB):]
            if R_HEADS + n not in heads:
                self.bare_git.DeleteRef(name, ref_id)

    def GetUploadableBranches(self, selected_branch=None):
        """List any branches which can be uploaded for review.
        """
        heads = {}
        pubed = {}

        for name, ref_id in self._allrefs.items():
            if name.startswith(R_HEADS):
                heads[name[len(R_HEADS):]] = ref_id
            elif name.startswith(R_PUB):
                pubed[name[len(R_PUB):]] = ref_id

        ready = []
        for branch, ref_id in heads.items():
            if branch in pubed and pubed[branch] == ref_id:
                continue
            if selected_branch and branch != selected_branch:
                continue

            rb = self.GetUploadableBranch(branch)
            if rb:
                ready.append(rb)
        return ready

    def GetUploadableBranch(self, branch_name):
        """Get a single uploadable branch, or None.
        """
        branch = self.GetBranch(branch_name)
        base = branch.LocalMerge
        if branch.LocalMerge:
            rb = ReviewableBranch(self, branch, base)
            if rb.commits:
                return rb
        return None

    def GetPushableBranch(self, branch_name):
        """Get a single pushable branch, or None.
        """
        branch = self.GetBranch(branch_name)
        base = branch.LocalMerge
        if branch.LocalMerge:
            rb = ReviewableBranch(self, branch, base)
            return rb
        return None

    def  UploadNoReview(self, opt, peoples, branch=None):
        """If not review server defined, uploads the named branch directly to git server.
        """
        if branch is None:
            branch = self.CurrentBranch
        if branch is None:
            raise GitError('not currently on a branch')

        branch = self.GetBranch(branch)

        if not branch.LocalMerge:
            raise GitError('branch %s does not track a remote' % branch.name)

        # if not opt.ignore_review and branch.remote.review:
        #   raise GitError('remote %s has review url, use `repo upload` instead or use `repo push --`.' % branch.remote.name)

        if opt.new_branch:
            dest_branch = branch.name
        else:
            dest_branch = branch.merge

        if dest_branch.startswith(R_TAGS):
            raise GitError('Can not push to TAGS (%s)! Run repo push with --new flag to create new feature branch.' % dest_branch)
        if not dest_branch.startswith(R_HEADS):
            dest_branch = R_HEADS + dest_branch

        if not branch.remote.projectname:
            branch.remote.projectname = self.name
            branch.remote.Save()

        # save git config branch.name.merge
        if opt.new_branch:
            branch.merge = dest_branch
            branch.Save()

        ref_spec = '%s:%s' % (R_HEADS + branch.name, dest_branch)
        pushurl = self.manifest.manifestProject.config.GetString('repo.%s.pushurl'
                                                                 % branch.remote.name)
        if not pushurl:
            pushurl = self.manifest.manifestProject.config.GetString('repo.pushurl')
        if not pushurl:
            html_url = self._UserUrl.rstrip('/') + '/'
            namespace = self._GitcodeNamespace(html_url, type='upload')
            pushurl = ':'.join([GITCODE_SSH, namespace])
            self.manifest.manifestProject.config.SetString('repo.pushurl', pushurl)
            # pushurl = branch.remote.name
        pushurl = pushurl.rstrip('/') + '/' + self.name
        # remote = self.manifest.remotes.get(branch.remote.name)
        # if remote and remote.autodotgit is not False:
        #   pushurl += ".git"

        cmd = ['push']
        if opt.force:
            cmd.append('--force')
        cmd.append(pushurl)
        cmd.append(ref_spec)

        if GitCommand(self, cmd).Wait() != 0:
            raise UploadError('Upload failed')

        if branch.LocalMerge and branch.LocalMerge.startswith('refs/remotes'):
            self.bare_git.UpdateRef(branch.LocalMerge,
                                    R_HEADS + branch.name)

    def PullRequest(self, opt, branch, peoples):
        """curl --location --request GET 'https://api.gitcode.com/api/v5/repos/{owner}/{repo}/pulls' \
          -d '{"access_token":"token",	       --header 'private-token: token' \
        "title":"test_repo","head":"repo_test","base":"master"}'
        use remote.url to generate post_url
        """
        if opt.dest_branch:
            base_branch = opt.dest_branch
        elif self.revisionExpr:
            base_branch = self.revisionExpr
            print("project revisionExpr %s" % self.revisionExpr)
        else:
            print("default revisionExpr %s" % self.manifest.default.revisionExpr)
            base_branch = self.manifest.default.revisionExpr

        namespace = self._GitcodeNamespace()
        token = self.manifest.manifestProject.config.GetString('repo.token')
        if not token:
            token = GitConfig.ForUser().GetString('repo.token')
            if not token:
                raise PullRequestError('repo.token is None, Please set it before pushing, you need `repo config -h`')

        post_url = '/'.join([GITCODE_PR_V5_API, namespace, self.name, 'pulls'])
        pushurl = self.manifest.manifestProject.config.GetString('repo.pushurl')
        if not pushurl:
            head = branch
        else:
            pushurl = pushurl.rstrip('/') + '/'
            head = ':'.join([self._GitcodeNamespace(pushurl), branch])

        payload = {"title": opt.title or 'Gitee Review - {}'.format(branch), "head": head,
                   "base": base_branch, "assignees": ','.join(peoples)}
        if opt.content:
            payload['description'] = opt.content
        try:
            r = requests.post(post_url +"?access_token=" + token, json=payload, timeout=TIMEOUT)
        except requests.exceptions.RequestException as e:
            raise PullRequestError('requests error: %s' % e)

        r_j = r.json()
        if r.status_code != 200:
            error_message = r_j['error_message']
            raise PullRequestError('pull request %s  code :%s  error: %s' %
                                   (post_url, r.status_code, error_message))
        return r_j['web_url']

    def ForkProject(self, token=None):
        if not token:
            token = self.manifest.manifestProject.config.GetString('repo.token')
            if not token:
                token = GitConfig.ForUser().GetString('repo.token')
                if not token:
                    raise ForkProjectError('repo.token is None, Please set it before pushing, you need `repo config -h`')
        namespace = self._GitcodeNamespace(type='forkproject')
        project_id = '%2F'.join([namespace, self.name])
        post_url = '/'.join([GITCODE_PR_V3_API, project_id, 'fork'])
        payload = {}
        headers={'private-token': token}
        try:
            r = requests.post(post_url, json=payload, headers=headers,timeout=TIMEOUT)
        except requests.exceptions.RequestException as e:
            raise ForkProjectError('requests error: %s' % e)
        msg = r.json()
        return r.status_code, msg

    def _GitcodeNamespace(self, url=None, type='pullrequest'):
        check_url = url if url is not None else self.remote.url
        regex1 = r'^git@gitcode.com:(.*?)/.*'
        regex2 = r'^https://.*gitcode.com/(.*?)/.*'
        name1 = re.match(regex1, check_url)
        name2 = re.match(regex2, check_url)
        if name1:
            return name1.group(1)
        elif name2:
            return name2.group(1)
        else:
            if type == 'pullrequest':
                raise PullRequestError("remote.url: %s doesn't belong to gitcode" % check_url)
            elif type == 'forkproject':
                raise ForkProjectError("remote.url: %s doesn't belong to gitcode" % check_url)
            else:
                raise UploadError("remote.url: %s doesn't belong to gitcode" % check_url)

    @property
    def _UserUrl(self):
        token = self.manifest.manifestProject.config.GetString('repo.token')
        if not token:
            token = GitConfig.ForUser().GetString('repo.token')
            if not token:
                raise UploadError('repo.token is None, Please set it, you need `repo config -h`')
        payload = {'access_token': token}
        try:
            r = requests.get(GITCODE_USER_API, params=payload, timeout=TIMEOUT)
        except requests.exceptions.RequestException as e:
            raise UploadError('requests error: %s' % e)
        if r.status_code != 200:
            raise UploadError('repo.token is Error, Please reset')
        return r.json()['html_url']

    def UploadForReview(self, branch=None,
                        people=([], []),
                        dryrun=False,
                        auto_topic=False,
                        hashtags=(),
                        labels=(),
                        private=False,
                        notify=None,
                        wip=False,
                        dest_branch=None,
                        validate_certs=True,
                        push_options=None):
        """Uploads the named branch for code review.
        """
        if branch is None:
            branch = self.CurrentBranch
        if branch is None:
            raise GitError('not currently on a branch')

        branch = self.GetBranch(branch)
        if not branch.LocalMerge:
            raise GitError('branch %s does not track a remote' % branch.name)
        if not branch.remote.review:
            raise GitError('remote %s has no review url' % branch.remote.name)

        if dest_branch is None:
            dest_branch = self.dest_branch
        if dest_branch is None:
            dest_branch = branch.merge
        if not dest_branch.startswith(R_HEADS):
            dest_branch = R_HEADS + dest_branch

        if not branch.remote.projectname:
            branch.remote.projectname = self.name
            branch.remote.Save()

        url = branch.remote.ReviewUrl(self.UserEmail, validate_certs)
        if url is None:
            raise UploadError('review not configured')
        cmd = ['push']
        if dryrun:
            cmd.append('-n')

        if url.startswith('ssh://'):
            cmd.append('--receive-pack=gerrit receive-pack')

        for push_option in (push_options or []):
            cmd.append('-o')
            cmd.append(push_option)

        cmd.append(url)

        if dest_branch.startswith(R_HEADS):
            dest_branch = dest_branch[len(R_HEADS):]

        ref_spec = '%s:refs/for/%s' % (R_HEADS + branch.name, dest_branch)
        opts = []
        if auto_topic:
            opts += ['topic=' + branch.name]
        opts += ['t=%s' % p for p in hashtags]
        opts += ['l=%s' % p for p in labels]

        opts += ['r=%s' % p for p in people[0]]
        opts += ['cc=%s' % p for p in people[1]]
        if notify:
            opts += ['notify=' + notify]
        if private:
            opts += ['private']
        if wip:
            opts += ['wip']
        if opts:
            ref_spec = ref_spec + '%' + ','.join(opts)
        cmd.append(ref_spec)

        if GitCommand(self, cmd, bare=True).Wait() != 0:
            raise UploadError('Upload failed')

        msg = "posted to %s for %s" % (branch.remote.review, dest_branch)
        self.bare_git.UpdateRef(R_PUB + branch.name,
                                R_HEADS + branch.name,
                                message=msg)

    # Sync ##
    def _ExtractArchive(self, tarpath, path=None):
        """Extract the given tar on its current location

        Args:
            - tarpath: The path to the actual tar file

        """
        try:
            with tarfile.open(tarpath, 'r') as tar:
                tar.extractall(path=path)
                return True
        except (IOError, tarfile.TarError) as e:
            _error("Cannot extract archive %s: %s", tarpath, str(e))
        return False

    def Sync_NetworkHalf(self,
                         quiet=False,
                         verbose=False,
                         is_new=None,
                         current_branch_only=False,
                         force_sync=False,
                         clone_bundle=True,
                         tags=True,
                         archive=False,
                         optimized_fetch=False,
                         retry_fetches=0,
                         prune=False,
                         submodules=False,
                         clone_filter=None):
        """Perform only the network IO portion of the sync process.
           Local working directory/branch state is not affected.
        """
        if archive and not isinstance(self, MetaProject):
            if self.remote.url.startswith(('http://', 'https://')):
                _error("%s: Cannot fetch archives from http/https remotes.", self.name)
                return False

            name = self.relpath.replace('\\', '/')
            name = name.replace('/', '_')
            tarpath = '%s.tar' % name
            topdir = self.manifest.topdir

            try:
                self._FetchArchive(tarpath, cwd=topdir)
            except GitError as e:
                _error('%s', e)
                return False

            # From now on, we only need absolute tarpath
            tarpath = os.path.join(topdir, tarpath)

            if not self._ExtractArchive(tarpath, path=topdir):
                return False
            try:
                platform_utils.remove(tarpath)
            except OSError as e:
                _warn("Cannot remove archive %s: %s", tarpath, str(e))
            self._CopyAndLinkFiles()
            return True
        if is_new is None:
            is_new = not self.Exists
        if is_new:
            self._InitGitDir(force_sync=force_sync, quiet=quiet)
        else:
            self._UpdateHooks(quiet=quiet)
        self._InitRemote()

        if is_new:
            alt = os.path.join(self.gitdir, 'objects/info/alternates')
            try:
                with open(alt) as fd:
                    # This works for both absolute and relative alternate directories.
                    alt_dir = os.path.join(self.objdir, 'objects', fd.readline().rstrip())
            except IOError:
                alt_dir = None
        else:
            alt_dir = None

        if (clone_bundle
                and alt_dir is None
                and self._ApplyCloneBundle(initial=is_new, quiet=quiet, verbose=verbose)):
            is_new = False

        if not current_branch_only:
            if self.sync_c:
                current_branch_only = True
            elif not self.manifest._loaded:
                # Manifest cannot check defaults until it syncs.
                current_branch_only = False
            elif self.manifest.default.sync_c:
                current_branch_only = True

        if not self.sync_tags:
            tags = False

        if self.clone_depth:
            depth = self.clone_depth
        else:
            depth = self.manifest.manifestProject.config.GetString('repo.depth')

        # See if we can skip the network fetch entirely.
        if not (optimized_fetch and
                (ID_RE.match(self.revisionExpr) and
                 self._CheckForImmutableRevision())):
            if not self._RemoteFetch(
                    initial=is_new, quiet=quiet, verbose=verbose, alt_dir=alt_dir,
                    current_branch_only=current_branch_only,
                    tags=tags, prune=prune, depth=depth,
                    submodules=submodules, force_sync=force_sync,
                    clone_filter=clone_filter, retry_fetches=retry_fetches):
                return False

        mp = self.manifest.manifestProject
        dissociate = mp.config.GetBoolean('repo.dissociate')
        if dissociate:
            alternates_file = os.path.join(self.gitdir, 'objects/info/alternates')
            if os.path.exists(alternates_file):
                cmd = ['repack', '-a', '-d']
                if GitCommand(self, cmd, bare=True).Wait() != 0:
                    return False
                platform_utils.remove(alternates_file)

        if self.worktree:
            self._InitMRef()
        else:
            self._InitMirrorHead()
            try:
                platform_utils.remove(os.path.join(self.gitdir, 'FETCH_HEAD'))
            except OSError:
                pass
        return True

    def PostRepoUpgrade(self):
        self._InitHooks()

    def _CopyAndLinkFiles(self):
        if self.manifest.isGitcClient:
            return
        for copyfile in self.copyfiles:
            copyfile._Copy()
        for linkfile in self.linkfiles:
            linkfile._Link()

    def GetCommitRevisionId(self):
        """Get revisionId of a commit.

        Use this method instead of GetRevisionId to get the id of the commit rather
        than the id of the current git object (for example, a tag)

        """
        if not self.revisionExpr.startswith(R_TAGS):
            return self.GetRevisionId(self._allrefs)

        try:
            return self.bare_git.rev_list(self.revisionExpr, '-1')[0]
        except GitError:
            raise ManifestInvalidRevisionError('revision %s in %s not found' %
                                               (self.revisionExpr, self.name))

    def GetRevisionId(self, all_refs=None):
        if self.revisionId:
            return self.revisionId

        rem = self.GetRemote(self.remote.name)
        rev = rem.ToLocal(self.revisionExpr)

        if all_refs is not None and rev in all_refs:
            return all_refs[rev]

        try:
            return self.bare_git.rev_parse('--verify', '%s^0' % rev)
        except GitError:
            raise ManifestInvalidRevisionError('revision %s in %s not found' %
                                               (self.revisionExpr, self.name))

    def Sync_LocalHalf(self, syncbuf, force_sync=False, submodules=False):
        """Perform only the local IO portion of the sync process.
           Network access is not required.
        """
        if not os.path.exists(self.gitdir):
            syncbuf.fail(self,
                         'Cannot checkout %s due to missing network sync; Run '
                         '`repo sync -n %s` first.' %
                         (self.name, self.name))
            return

        self._InitWorkTree(force_sync=force_sync, submodules=submodules)
        all_refs = self.bare_ref.all
        self.CleanPublishedCache(all_refs)
        revid = self.GetRevisionId(all_refs)

        def _doff():
            self._FastForward(revid)
            self._CopyAndLinkFiles()

        def _dosubmodules():
            self._SyncSubmodules(quiet=True)

        head = self.work_git.GetHead()
        if head.startswith(R_HEADS):
            branch = head[len(R_HEADS):]
            try:
                head = all_refs[head]
            except KeyError:
                head = None
        else:
            branch = None

        if branch is None or syncbuf.detach_head:
            # Currently on a detached HEAD.  The user is assumed to
            # not have any local modifications worth worrying about.
            #
            if self.IsRebaseInProgress():
                syncbuf.fail(self, _PriorSyncFailedError())
                return

            if head == revid:
                # No changes; don't do anything further.
                # Except if the head needs to be detached
                #
                if not syncbuf.detach_head:
                    # The copy/linkfile config may have changed.
                    self._CopyAndLinkFiles()
                    return
            else:
                lost = self._revlist(not_rev(revid), HEAD)
                if lost:
                    syncbuf.info(self, "discarding %d commits", len(lost))

            try:
                self._Checkout(revid, quiet=True)
                if submodules:
                    self._SyncSubmodules(quiet=True)
            except GitError as e:
                syncbuf.fail(self, e)
                return
            self._CopyAndLinkFiles()
            return

        if head == revid:
            # No changes; don't do anything further.
            #
            # The copy/linkfile config may have changed.
            self._CopyAndLinkFiles()
            return

        branch = self.GetBranch(branch)

        if not branch.LocalMerge:
            # The current branch has no tracking configuration.
            # Jump off it to a detached HEAD.
            #
            syncbuf.info(self,
                         "leaving %s; does not track upstream",
                         branch.name)
            try:
                self._Checkout(revid, quiet=True)
                if submodules:
                    self._SyncSubmodules(quiet=True)
            except GitError as e:
                syncbuf.fail(self, e)
                return
            self._CopyAndLinkFiles()
            return

        upstream_gain = self._revlist(not_rev(HEAD), revid)

        # See if we can perform a fast forward merge.  This can happen if our
        # branch isn't in the exact same state as we last published.
        try:
            self.work_git.merge_base('--is-ancestor', HEAD, revid)
            # Skip the published logic.
            pub = False
        except GitError:
            pub = self.WasPublished(branch.name, all_refs)

        if pub:
            not_merged = self._revlist(not_rev(revid), pub)
            if not_merged:
                if upstream_gain:
                    # The user has published this branch and some of those
                    # commits are not yet merged upstream.  We do not want
                    # to rewrite the published commits so we punt.
                    #
                    syncbuf.fail(self,
                                 "branch %s is published (but not merged) and is now "
                                 "%d commits behind" % (branch.name, len(upstream_gain)))
                return
            elif pub == head:
                # All published commits are merged, and thus we are a
                # strict subset.  We can fast-forward safely.
                #
                syncbuf.later1(self, _doff)
                if submodules:
                    syncbuf.later1(self, _dosubmodules)
                return

        # Examine the local commits not in the remote.  Find the
        # last one attributed to this user, if any.
        #
        local_changes = self._revlist(not_rev(revid), HEAD, format='%H %ce')
        last_mine = None
        cnt_mine = 0
        for commit in local_changes:
            commit_id, committer_email = commit.split(' ', 1)
            if committer_email == self.UserEmail:
                last_mine = commit_id
                cnt_mine += 1

        if not upstream_gain and cnt_mine == len(local_changes):
            return

        if self.IsDirty(consider_untracked=False):
            syncbuf.fail(self, _DirtyError())
            return

        # If the upstream switched on us, warn the user.
        #
        if branch.merge != self.revisionExpr:
            if branch.merge and self.revisionExpr:
                syncbuf.info(self,
                             'manifest switched %s...%s',
                             branch.merge,
                             self.revisionExpr)
            elif branch.merge:
                syncbuf.info(self,
                             'manifest no longer tracks %s',
                             branch.merge)

        if cnt_mine < len(local_changes):
            # Upstream rebased.  Not everything in HEAD
            # was created by this user.
            #
            syncbuf.info(self,
                         "discarding %d commits removed from upstream",
                         len(local_changes) - cnt_mine)

        branch.remote = self.GetRemote(self.remote.name)
        if not ID_RE.match(self.revisionExpr):
            # in case of manifest sync the revisionExpr might be a SHA1
            branch.merge = self.revisionExpr
            if not branch.merge.startswith('refs/'):
                branch.merge = R_HEADS + branch.merge
        branch.Save()

        if cnt_mine > 0 and self.rebase:
            def _docopyandlink():
                self._CopyAndLinkFiles()

            def _dorebase():
                self._Rebase(upstream='%s^1' % last_mine, onto=revid)
            syncbuf.later2(self, _dorebase)
            if submodules:
                syncbuf.later2(self, _dosubmodules)
            syncbuf.later2(self, _docopyandlink)
        elif local_changes:
            try:
                self._ResetHard(revid)
                if submodules:
                    self._SyncSubmodules(quiet=True)
                self._CopyAndLinkFiles()
            except GitError as e:
                syncbuf.fail(self, e)
                return
        else:
            syncbuf.later1(self, _doff)
            if submodules:
                syncbuf.later1(self, _dosubmodules)

    def AddCopyFile(self, src, dest, topdir):
        """Mark |src| for copying to |dest| (relative to |topdir|).

        No filesystem changes occur here.  Actual copying happens later on.

        Paths should have basic validation run on them before being queued.
        Further checking will be handled when the actual copy happens.
        """
        self.copyfiles.append(_CopyFile(self.worktree, src, topdir, dest))

    def AddLinkFile(self, src, dest, topdir):
        """Mark |dest| to create a symlink (relative to |topdir|) pointing to |src|.

        No filesystem changes occur here.  Actual linking happens later on.

        Paths should have basic validation run on them before being queued.
        Further checking will be handled when the actual link happens.
        """
        self.linkfiles.append(_LinkFile(self.worktree, src, topdir, dest))

    def AddAnnotation(self, name, value, keep):
        self.annotations.append(_Annotation(name, value, keep))

    def DownloadPatchSet(self, change_id, patch_id):
        """Download a single patch set of a single change to FETCH_HEAD.
        """
        remote = self.GetRemote(self.remote.name)

        cmd = ['fetch', remote.name]
        cmd.append('refs/changes/%2.2d/%d/%d'
                   % (change_id % 100, change_id, patch_id))
        if GitCommand(self, cmd, bare=True).Wait() != 0:
            return None
        return DownloadedChange(self,
                                self.GetRevisionId(),
                                change_id,
                                patch_id,
                                self.bare_git.rev_parse('FETCH_HEAD'))

    def DeleteWorktree(self, quiet=False, force=False):
        """Delete the source checkout and any other housekeeping tasks.

        This currently leaves behind the internal .repo/ cache state.  This helps
        when switching branches or manifest changes get reverted as we don't have
        to redownload all the git objects.  But we should do some GC at some point.

        Args:
          quiet: Whether to hide normal messages.
          force: Always delete tree even if dirty.

        Returns:
          True if the worktree was completely cleaned out.
        """
        if self.IsDirty():
            if force:
                print('warning: %s: Removing dirty project: uncommitted changes lost.' %
                      (self.relpath,), file=sys.stderr)
            else:
                print('error: %s: Cannot remove project: uncommitted changes are '
                      'present.\n' % (self.relpath,), file=sys.stderr)
                return False

        if not quiet:
            print('%s: Deleting obsolete checkout.' % (self.relpath,))

        # Unlock and delink from the main worktree.  We don't use git's worktree
        # remove because it will recursively delete projects -- we handle that
        # ourselves below.  https://crbug.com/git/48
        if self.use_git_worktrees:
            needle = platform_utils.realpath(self.gitdir)
            # Find the git worktree commondir under .repo/worktrees/.
            output = self.bare_git.worktree('list', '--porcelain').splitlines()[0]
            assert output.startswith('worktree '), output
            commondir = output[9:]
            # Walk each of the git worktrees to see where they point.
            configs = os.path.join(commondir, 'worktrees')
            for name in os.listdir(configs):
                gitdir = os.path.join(configs, name, 'gitdir')
                with open(gitdir) as fp:
                    relpath = fp.read().strip()
                # Resolve the checkout path and see if it matches this project.
                fullpath = platform_utils.realpath(os.path.join(configs, name, relpath))
                if fullpath == needle:
                    platform_utils.rmtree(os.path.join(configs, name))

        # Delete the .git directory first, so we're less likely to have a partially
        # working git repository around. There shouldn't be any git projects here,
        # so rmtree works.

        # Try to remove plain files first in case of git worktrees.  If this fails
        # for any reason, we'll fall back to rmtree, and that'll display errors if
        # it can't remove things either.
        try:
            platform_utils.remove(self.gitdir)
        except OSError:
            pass
        try:
            platform_utils.rmtree(self.gitdir)
        except OSError as e:
            if e.errno != errno.ENOENT:
                print('error: %s: %s' % (self.gitdir, e), file=sys.stderr)
                print('error: %s: Failed to delete obsolete checkout; remove manually, '
                      'then run `repo sync -l`.' % (self.relpath,), file=sys.stderr)
                return False

        # Delete everything under the worktree, except for directories that contain
        # another git project.
        dirs_to_remove = []
        failed = False
        for root, dirs, files in platform_utils.walk(self.worktree):
            for f in files:
                path = os.path.join(root, f)
                try:
                    platform_utils.remove(path)
                except OSError as e:
                    if e.errno != errno.ENOENT:
                        print('error: %s: Failed to remove: %s' % (path, e), file=sys.stderr)
                        failed = True
            dirs[:] = [d for d in dirs
                       if not os.path.lexists(os.path.join(root, d, '.git'))]
            dirs_to_remove += [os.path.join(root, d) for d in dirs
                               if os.path.join(root, d) not in dirs_to_remove]
        for d in reversed(dirs_to_remove):
            if platform_utils.islink(d):
                try:
                    platform_utils.remove(d)
                except OSError as e:
                    if e.errno != errno.ENOENT:
                        print('error: %s: Failed to remove: %s' % (d, e), file=sys.stderr)
                        failed = True
            elif not platform_utils.listdir(d):
                try:
                    platform_utils.rmdir(d)
                except OSError as e:
                    if e.errno != errno.ENOENT:
                        print('error: %s: Failed to remove: %s' % (d, e), file=sys.stderr)
                        failed = True
        if failed:
            print('error: %s: Failed to delete obsolete checkout.' % (self.relpath,),
                  file=sys.stderr)
            print('       Remove manually, then run `repo sync -l`.', file=sys.stderr)
            return False

        # Try deleting parent dirs if they are empty.
        path = self.worktree
        while path != self.manifest.topdir:
            try:
                platform_utils.rmdir(path)
            except OSError as e:
                if e.errno != errno.ENOENT:
                    break
            path = os.path.dirname(path)

        return True

    # Branch Management ##
    def StartBranch(self, name, branch_merge='', revision=None):
        """Create a new branch off the manifest's revision.
        """
        if not branch_merge:
            branch_merge = self.revisionExpr
        head = self.work_git.GetHead()
        if head == (R_HEADS + name):
            return True

        all_refs = self.bare_ref.all
        if R_HEADS + name in all_refs:
            return GitCommand(self,
                              ['checkout', name, '--'],
                              capture_stdout=True,
                              capture_stderr=True).Wait() == 0

        branch = self.GetBranch(name)
        branch.remote = self.GetRemote(self.remote.name)
        branch.merge = branch_merge
        if not branch.merge.startswith('refs/') and not ID_RE.match(branch_merge):
            branch.merge = R_HEADS + branch_merge

        if revision is None:
            revid = self.GetRevisionId(all_refs)
        else:
            revid = self.work_git.rev_parse(revision)

        if head.startswith(R_HEADS):
            try:
                head = all_refs[head]
            except KeyError:
                head = None
        if revid and head and revid == head:
            ref = R_HEADS + name
            self.work_git.update_ref(ref, revid)
            self.work_git.symbolic_ref(HEAD, ref)
            branch.Save()
            return True

        if GitCommand(self,
                      ['checkout', '-b', branch.name, revid],
                      capture_stdout=True,
                      capture_stderr=True).Wait() == 0:
            branch.Save()
            return True
        return False

    def CheckoutBranch(self, name):
        """Checkout a local topic branch.

            Args:
              name: The name of the branch to checkout.

            Returns:
              True if the checkout succeeded; False if it didn't; None if the branch
              didn't exist.
        """
        rev = R_HEADS + name
        head = self.work_git.GetHead()
        if head == rev:
            # Already on the branch
            #
            return True

        all_refs = self.bare_ref.all
        try:
            revid = all_refs[rev]
        except KeyError:
            # Branch does not exist in this project
            #
            return None

        if head.startswith(R_HEADS):
            try:
                head = all_refs[head]
            except KeyError:
                head = None

        if head == revid:
            # Same revision; just update HEAD to point to the new
            # target branch, but otherwise take no other action.
            #
            _lwrite(self.work_git.GetDotgitPath(subpath=HEAD),
                    'ref: %s%s\n' % (R_HEADS, name))
            return True

        return GitCommand(self,
                          ['checkout', name, '--'],
                          capture_stdout=True,
                          capture_stderr=True).Wait() == 0

    def AbandonBranch(self, name):
        """Destroy a local topic branch.

        Args:
          name: The name of the branch to abandon.

        Returns:
          True if the abandon succeeded; False if it didn't; None if the branch
          didn't exist.
        """
        rev = R_HEADS + name
        all_refs = self.bare_ref.all
        if rev not in all_refs:
            # Doesn't exist
            return None

        head = self.work_git.GetHead()
        if head == rev:
            # We can't destroy the branch while we are sitting
            # on it.  Switch to a detached HEAD.
            #
            head = all_refs[head]

            revid = self.GetRevisionId(all_refs)
            if head == revid:
                _lwrite(self.work_git.GetDotgitPath(subpath=HEAD), '%s\n' % revid)
            else:
                self._Checkout(revid, quiet=True)

        return GitCommand(self,
                          ['branch', '-D', name],
                          capture_stdout=True,
                          capture_stderr=True).Wait() == 0

    def PruneHeads(self):
        """Prune any topic branches already merged into upstream.
        """
        cb = self.CurrentBranch
        kill = []
        left = self._allrefs
        for name in left.keys():
            if name.startswith(R_HEADS):
                name = name[len(R_HEADS):]
                if cb is None or name != cb:
                    kill.append(name)

        rev = self.GetRevisionId(left)
        if cb is not None \
                and not self._revlist(HEAD + '...' + rev) \
                and not self.IsDirty(consider_untracked=False):
            self.work_git.DetachHead(HEAD)
            kill.append(cb)

        if kill:
            old = self.bare_git.GetHead()

            try:
                self.bare_git.DetachHead(rev)

                b = ['branch', '-d']
                b.extend(kill)
                b = GitCommand(self, b, bare=True,
                               capture_stdout=True,
                               capture_stderr=True)
                b.Wait()
            finally:
                if ID_RE.match(old):
                    self.bare_git.DetachHead(old)
                else:
                    self.bare_git.SetHead(old)
                left = self._allrefs

            for branch in kill:
                if (R_HEADS + branch) not in left:
                    self.CleanPublishedCache()
                    break

        if cb and cb not in kill:
            kill.append(cb)
        kill.sort()

        kept = []
        for branch in kill:
            if R_HEADS + branch in left:
                branch = self.GetBranch(branch)
                base = branch.LocalMerge
                if not base:
                    base = rev
                kept.append(ReviewableBranch(self, branch, base))
        return kept

    # Submodule Management ##
    def GetRegisteredSubprojects(self):
        result = []

        def rec(subprojects):
            if not subprojects:
                return
            result.extend(subprojects)
            for p in subprojects:
                rec(p.subprojects)
        rec(self.subprojects)
        return result

    def _GetSubmodules(self):
        # Unfortunately we cannot call `git submodule status --recursive` here
        # because the working tree might not exist yet, and it cannot be used
        # without a working tree in its current implementation.

        def get_submodules(gitdir, rev):
            # Parse .gitmodules for submodule sub_paths and sub_urls
            sub_paths, sub_urls = parse_gitmodules(gitdir, rev)
            if not sub_paths:
                return []
            # Run `git ls-tree` to read SHAs of submodule object, which happen to be
            # revision of submodule repository
            sub_revs = git_ls_tree(gitdir, rev, sub_paths)
            submodules = []
            for sub_path, sub_url in zip(sub_paths, sub_urls):
                try:
                    sub_rev = sub_revs[sub_path]
                except KeyError:
                    # Ignore non-exist submodules
                    continue
                submodules.append((sub_rev, sub_path, sub_url))
            return submodules

        re_path = re.compile(r'^submodule\.(.+)\.path=(.*)$')
        re_url = re.compile(r'^submodule\.(.+)\.url=(.*)$')

        def parse_gitmodules(gitdir, rev):
            cmd = ['cat-file', 'blob', '%s:.gitmodules' % rev]
            try:
                p = GitCommand(None, cmd, capture_stdout=True, capture_stderr=True,
                               bare=True, gitdir=gitdir)
            except GitError:
                return [], []
            if p.Wait() != 0:
                return [], []

            gitmodules_lines = []
            fd, temp_gitmodules_path = tempfile.mkstemp()
            try:
                os.write(fd, p.stdout.encode('utf-8'))
                os.close(fd)
                cmd = ['config', '--file', temp_gitmodules_path, '--list']
                p = GitCommand(None, cmd, capture_stdout=True, capture_stderr=True,
                               bare=True, gitdir=gitdir)
                if p.Wait() != 0:
                    return [], []
                gitmodules_lines = p.stdout.split('\n')
            except GitError:
                return [], []
            finally:
                platform_utils.remove(temp_gitmodules_path)

            names = set()
            paths = {}
            urls = {}
            for line in gitmodules_lines:
                if not line:
                    continue
                m = re_path.match(line)
                if m:
                    names.add(m.group(1))
                    paths[m.group(1)] = m.group(2)
                    continue
                m = re_url.match(line)
                if m:
                    names.add(m.group(1))
                    urls[m.group(1)] = m.group(2)
                    continue
            names = sorted(names)
            return ([paths.get(name, '') for name in names],
                    [urls.get(name, '') for name in names])

        def git_ls_tree(gitdir, rev, paths):
            cmd = ['ls-tree', rev, '--']
            cmd.extend(paths)
            try:
                p = GitCommand(None, cmd, capture_stdout=True, capture_stderr=True,
                               bare=True, gitdir=gitdir)
            except GitError:
                return []
            if p.Wait() != 0:
                return []
            objects = {}
            for line in p.stdout.split('\n'):
                if not line.strip():
                    continue
                object_rev, object_path = line.split()[2:4]
                objects[object_path] = object_rev
            return objects

        try:
            rev = self.GetRevisionId()
        except GitError:
            return []
        return get_submodules(self.gitdir, rev)

    def GetDerivedSubprojects(self):
        result = []
        if not self.Exists:
            # If git repo does not exist yet, querying its submodules will
            # mess up its states; so return here.
            return result
        for rev, path, url in self._GetSubmodules():
            name = self.manifest.GetSubprojectName(self, path)
            relpath, worktree, gitdir, objdir = \
                self.manifest.GetSubprojectPaths(self, name, path)
            project = self.manifest.paths.get(relpath)
            if project:
                result.extend(project.GetDerivedSubprojects())
                continue

            if url.startswith('..'):
                url = urllib.parse.urljoin("%s/" % self.remote.url, url)
            remote = RemoteSpec(self.remote.name,
                                url=url,
                                pushUrl=self.remote.pushUrl,
                                review=self.remote.review,
                                revision=self.remote.revision)
            subproject = Project(manifest=self.manifest,
                                 name=name,
                                 remote=remote,
                                 gitdir=gitdir,
                                 objdir=objdir,
                                 worktree=worktree,
                                 relpath=relpath,
                                 revisionExpr=rev,
                                 revisionId=rev,
                                 rebase=self.rebase,
                                 groups=self.groups,
                                 sync_c=self.sync_c,
                                 sync_s=self.sync_s,
                                 sync_tags=self.sync_tags,
                                 parent=self,
                                 is_derived=True)
            result.append(subproject)
            result.extend(subproject.GetDerivedSubprojects())
        return result

    # Direct Git Commands ##
    def EnableRepositoryExtension(self, key, value='true', version=1):
        """Enable git repository extension |key| with |value|.

        Args:
          key: The extension to enabled.  Omit the "extensions." prefix.
          value: The value to use for the extension.
          version: The minimum git repository version needed.
        """
        # Make sure the git repo version is new enough already.
        found_version = self.config.GetInt('core.repositoryFormatVersion')
        if found_version is None:
            found_version = 0
        if found_version < version:
            self.config.SetString('core.repositoryFormatVersion', str(version))

        # Enable the extension!
        self.config.SetString('extensions.%s' % (key,), value)

    def _CheckForImmutableRevision(self):
        try:
            # if revision (sha or tag) is not present then following function
            # throws an error.
            self.bare_git.rev_parse('--verify', '%s^0' % self.revisionExpr)
            return True
        except GitError:
            # There is no such persistent revision. We have to fetch it.
            return False

    def _FetchArchive(self, tarpath, cwd=None):
        cmd = ['archive', '-v', '-o', tarpath]
        cmd.append('--remote=%s' % self.remote.url)
        cmd.append('--prefix=%s/' % self.relpath)
        cmd.append(self.revisionExpr)

        command = GitCommand(self, cmd, cwd=cwd,
                             capture_stdout=True,
                             capture_stderr=True)

        if command.Wait() != 0:
            raise GitError('git archive %s: %s' % (self.name, command.stderr))

    def _RemoteFetch(self, name=None,
                     current_branch_only=False,
                     initial=False,
                     quiet=False,
                     verbose=False,
                     alt_dir=None,
                     tags=True,
                     prune=False,
                     depth=None,
                     submodules=False,
                     force_sync=False,
                     clone_filter=None,
                     retry_fetches=2,
                     retry_sleep_initial_sec=4.0,
                     retry_exp_factor=2.0):
        is_sha1 = False
        tag_name = None
        # The depth should not be used when fetching to a mirror because
        # it will result in a shallow repository that cannot be cloned or
        # fetched from.
        # The repo project should also never be synced with partial depth.
        if self.manifest.IsMirror or self.relpath == '.repo/repo':
            depth = None

        if depth:
            current_branch_only = True

        if ID_RE.match(self.revisionExpr) is not None:
            is_sha1 = True

        if current_branch_only:
            if self.revisionExpr.startswith(R_TAGS):
                # this is a tag and its sha1 value should never change
                tag_name = self.revisionExpr[len(R_TAGS):]

            if is_sha1 or tag_name is not None:
                if self._CheckForImmutableRevision():
                    if verbose:
                        print('Skipped fetching project %s (already have persistent ref)'
                              % self.name)
                    return True
            if is_sha1 and not depth:
                # When syncing a specific commit and --depth is not set:
                # * if upstream is explicitly specified and is not a sha1, fetch only
                #   upstream as users expect only upstream to be fetch.
                #   Note: The commit might not be in upstream in which case the sync
                #   will fail.
                # * otherwise, fetch all branches to make sure we end up with the
                #   specific commit.
                if self.upstream:
                    current_branch_only = not ID_RE.match(self.upstream)
                else:
                    current_branch_only = False

        if not name:
            name = self.remote.name

        ssh_proxy = False
        remote = self.GetRemote(name)
        if remote.PreConnectFetch():
            ssh_proxy = True

        if initial:
            if alt_dir and 'objects' == os.path.basename(alt_dir):
                ref_dir = os.path.dirname(alt_dir)
                packed_refs = os.path.join(self.gitdir, 'packed-refs')
                remote = self.GetRemote(name)

                all_refs = self.bare_ref.all
                ids = set(all_refs.values())
                tmp = set()

                for r, ref_id in GitRefs(ref_dir).all.items():
                    if r not in all_refs:
                        if r.startswith(R_TAGS) or remote.WritesTo(r):
                            all_refs[r] = ref_id
                            ids.add(ref_id)
                            continue

                    if ref_id in ids:
                        continue

                    r = 'refs/_alt/%s' % ref_id
                    all_refs[r] = ref_id
                    ids.add(ref_id)
                    tmp.add(r)

                tmp_packed_lines = []
                old_packed_lines = []

                for r in sorted(all_refs):
                    line = '%s %s\n' % (all_refs[r], r)
                    tmp_packed_lines.append(line)
                    if r not in tmp:
                        old_packed_lines.append(line)

                tmp_packed = ''.join(tmp_packed_lines)
                old_packed = ''.join(old_packed_lines)
                _lwrite(packed_refs, tmp_packed)
            else:
                alt_dir = None

        cmd = ['fetch']

        if clone_filter:
            git_require((2, 19, 0), fail=True, msg='partial clones')
            cmd.append('--filter=%s' % clone_filter)
            self.EnableRepositoryExtension('partialclone', self.remote.name)

        if depth:
            cmd.append('--depth=%s' % depth)
        else:
            # If this repo has shallow objects, then we don't know which refs have
            # shallow objects or not. Tell git to unshallow all fetched refs.  Don't
            # do this with projects that don't have shallow objects, since it is less
            # efficient.
            if os.path.exists(os.path.join(self.gitdir, 'shallow')):
                cmd.append('--depth=2147483647')

        if not verbose:
            cmd.append('--quiet')
        if not quiet and sys.stdout.isatty():
            cmd.append('--progress')
        if not self.worktree:
            cmd.append('--update-head-ok')
        cmd.append(name)

        if force_sync:
            cmd.append('--force')

        if prune:
            cmd.append('--prune')

        if submodules:
            cmd.append('--recurse-submodules=on-demand')

        spec = []
        if not current_branch_only:
            # Fetch whole repo
            spec.append(str((u'+refs/heads/*:') + remote.ToLocal('refs/heads/*')))
        elif tag_name is not None:
            spec.append('tag')
            spec.append(tag_name)

        if self.manifest.IsMirror and not current_branch_only:
            branch = None
        else:
            branch = self.revisionExpr
        if (not self.manifest.IsMirror and is_sha1 and depth
                and git_require((1, 8, 3))):
            # Shallow checkout of a specific commit, fetch from that commit and not
            # the heads only as the commit might be deeper in the history.
            spec.append(branch)
        else:
            if is_sha1:
                branch = self.upstream
            if branch is not None and branch.strip():
                if not branch.startswith('refs/'):
                    branch = R_HEADS + branch
                spec.append(str((u'+%s:' % branch) + remote.ToLocal(branch)))

        # If mirroring repo and we cannot deduce the tag or branch to fetch, fetch
        # whole repo.
        if self.manifest.IsMirror and not spec:
            spec.append(str((u'+refs/heads/*:') + remote.ToLocal('refs/heads/*')))

        # If using depth then we should not get all the tags since they may
        # be outside of the depth.
        if not tags or depth:
            cmd.append('--no-tags')
        else:
            cmd.append('--tags')
            spec.append(str((u'+refs/tags/*:') + remote.ToLocal('refs/tags/*')))

        cmd.extend(spec)

        # At least one retry minimum due to git remote prune.
        retry_fetches = max(retry_fetches, 2)
        retry_cur_sleep = retry_sleep_initial_sec
        ok = prune_tried = False
        for try_n in range(retry_fetches):
            gitcmd = GitCommand(self, cmd, bare=True, ssh_proxy=ssh_proxy,
                                merge_output=True, capture_stdout=quiet)
            ret = gitcmd.Wait()
            if ret == 0:
                ok = True
                break

            # Retry later due to HTTP 429 Too Many Requests.
            elif ('error:' in gitcmd.stderr and
                  'HTTP 429' in gitcmd.stderr):
                if not quiet:
                    print('429 received, sleeping: %s sec' % retry_cur_sleep,
                          file=sys.stderr)
                time.sleep(retry_cur_sleep)
                retry_cur_sleep = min(retry_exp_factor * retry_cur_sleep,
                                      MAXIMUM_RETRY_SLEEP_SEC)
                retry_cur_sleep *= (1 - random.uniform(-RETRY_JITTER_PERCENT,
                                                       RETRY_JITTER_PERCENT))
                continue

            # If this is not last attempt, try 'git remote prune'.
            elif (try_n < retry_fetches - 1 and
                  'error:' in gitcmd.stderr and
                  'git remote prune' in gitcmd.stderr and
                  not prune_tried):
                prune_tried = True
                prunecmd = GitCommand(self, ['remote', 'prune', name], bare=True,
                                      ssh_proxy=ssh_proxy)
                ret = prunecmd.Wait()
                if ret:
                    break
                continue
            elif current_branch_only and is_sha1 and ret == 128:
                # Exit code 128 means "couldn't find the ref you asked for"; if we're
                # in sha1 mode, we just tried sync'ing from the upstream field; it
                # doesn't exist, thus abort the optimization attempt and do a full sync.
                break
            elif ret < 0:
                # Git died with a signal, exit immediately
                break
            if not verbose:
                print('%s:\n%s' % (self.name, gitcmd.stdout), file=sys.stderr)
            time.sleep(random.randint(30, 45))

        if initial:
            if alt_dir:
                if old_packed != '':
                    _lwrite(packed_refs, old_packed)
                else:
                    platform_utils.remove(packed_refs)
            self.bare_git.pack_refs('--all', '--prune')

        if is_sha1 and current_branch_only:
            # We just synced the upstream given branch; verify we
            # got what we wanted, else trigger a second run of all
            # refs.
            if not self._CheckForImmutableRevision():
                # Sync the current branch only with depth set to None.
                # We always pass depth=None down to avoid infinite recursion.
                return self._RemoteFetch(
                    name=name, quiet=quiet, verbose=verbose,
                    current_branch_only=current_branch_only and depth,
                    initial=False, alt_dir=alt_dir,
                    depth=None, clone_filter=clone_filter)

        return ok

    def _ApplyCloneBundle(self, initial=False, quiet=False, verbose=False):
        if initial and \
                (self.manifest.manifestProject.config.GetString('repo.depth') or
                 self.clone_depth):
            return False

        remote = self.GetRemote(self.remote.name)
        bundle_url = remote.url + '/clone.bundle'
        bundle_url = GitConfig.ForUser().UrlInsteadOf(bundle_url)
        if GetSchemeFromUrl(bundle_url) not in ('http', 'https',
                                                'persistent-http',
                                                'persistent-https'):
            return False

        bundle_dst = os.path.join(self.gitdir, 'clone.bundle')
        bundle_tmp = os.path.join(self.gitdir, 'clone.bundle.tmp')

        exist_dst = os.path.exists(bundle_dst)
        exist_tmp = os.path.exists(bundle_tmp)

        if not initial and not exist_dst and not exist_tmp:
            return False

        if not exist_dst:
            exist_dst = self._FetchBundle(bundle_url, bundle_tmp, bundle_dst, quiet,
                                          verbose)
        if not exist_dst:
            return False

        cmd = ['fetch']
        if not verbose:
            cmd.append('--quiet')
        if not quiet and sys.stdout.isatty():
            cmd.append('--progress')
        if not self.worktree:
            cmd.append('--update-head-ok')
        cmd.append(bundle_dst)
        for f in remote.fetch:
            cmd.append(str(f))
        cmd.append('+refs/tags/*:refs/tags/*')

        ok = GitCommand(self, cmd, bare=True).Wait() == 0
        if os.path.exists(bundle_dst):
            platform_utils.remove(bundle_dst)
        if os.path.exists(bundle_tmp):
            platform_utils.remove(bundle_tmp)
        return ok

    def _FetchBundle(self, srcUrl, tmpPath, dstPath, quiet, verbose):
        if os.path.exists(dstPath):
            platform_utils.remove(dstPath)

        cmd = ['curl', '--fail', '--output', tmpPath, '--netrc', '--location']
        if quiet:
            cmd += ['--silent', '--show-error']
        if os.path.exists(tmpPath):
            size = os.stat(tmpPath).st_size
            if size >= 1024:
                cmd += ['--continue-at', '%d' % (size,)]
            else:
                platform_utils.remove(tmpPath)
        with GetUrlCookieFile(srcUrl, quiet) as (cookiefile, proxy):
            if cookiefile:
                cmd += ['--cookie', cookiefile]
            if proxy:
                cmd += ['--proxy', proxy]
            elif 'http_proxy' in os.environ and 'darwin' == sys.platform:
                cmd += ['--proxy', os.environ['http_proxy']]
            if srcUrl.startswith('persistent-https'):
                srcUrl = 'http' + srcUrl[len('persistent-https'):]
            elif srcUrl.startswith('persistent-http'):
                srcUrl = 'http' + srcUrl[len('persistent-http'):]
            cmd += [srcUrl]

            if IsTrace():
                Trace('%s', ' '.join(cmd))
            if verbose:
                print('%s: Downloading bundle: %s' % (self.name, srcUrl))
            stdout = None if verbose else subprocess.PIPE
            stderr = None if verbose else subprocess.STDOUT
            try:
                proc = subprocess.Popen(cmd, stdout=stdout, stderr=stderr)
            except OSError:
                return False

            (output, _) = proc.communicate()
            curlret = proc.returncode

            if curlret == 22:
                # From curl man page:
                # 22: HTTP page not retrieved. The requested url was not found or
                # returned another error with the HTTP error code being 400 or above.
                # This return code only appears if -f, --fail is used.
                if verbose:
                    print('%s: Unable to retrieve clone.bundle; ignoring.' % self.name)
                    if output:
                        print('Curl output:\n%s' % output)
                return False
            elif curlret and not verbose and output:
                print('%s' % output, file=sys.stderr)

        if os.path.exists(tmpPath):
            if curlret == 0 and self._IsValidBundle(tmpPath, quiet):
                platform_utils.rename(tmpPath, dstPath)
                return True
            else:
                platform_utils.remove(tmpPath)
                return False
        else:
            return False

    def _IsValidBundle(self, path, quiet):
        try:
            with open(path, 'rb') as f:
                if f.read(16) == b'# v2 git bundle\n':
                    return True
                else:
                    if not quiet:
                        print("Invalid clone.bundle file; ignoring.", file=sys.stderr)
                    return False
        except OSError:
            return False

    def _Checkout(self, rev, quiet=False):
        cmd = ['checkout']
        if quiet:
            cmd.append('-q')
        cmd.append(rev)
        cmd.append('--')
        if GitCommand(self, cmd).Wait() != 0:
            if self._allrefs:
                raise GitError('%s checkout %s ' % (self.name, rev))

    def _CherryPick(self, rev, ffonly=False, record_origin=False):
        cmd = ['cherry-pick']
        if ffonly:
            cmd.append('--ff')
        if record_origin:
            cmd.append('-x')
        cmd.append(rev)
        cmd.append('--')
        if GitCommand(self, cmd).Wait() != 0:
            if self._allrefs:
                raise GitError('%s cherry-pick %s ' % (self.name, rev))

    def _LsRemote(self, refs):
        cmd = ['ls-remote', self.remote.name, refs]
        p = GitCommand(self, cmd, capture_stdout=True)
        if p.Wait() == 0:
            return p.stdout
        return None

    def _Revert(self, rev):
        cmd = ['revert']
        cmd.append('--no-edit')
        cmd.append(rev)
        cmd.append('--')
        if GitCommand(self, cmd).Wait() != 0:
            if self._allrefs:
                raise GitError('%s revert %s ' % (self.name, rev))

    def _ResetHard(self, rev, quiet=True):
        cmd = ['reset', '--hard']
        if quiet:
            cmd.append('-q')
        cmd.append(rev)
        if GitCommand(self, cmd).Wait() != 0:
            raise GitError('%s reset --hard %s ' % (self.name, rev))

    def _SyncSubmodules(self, quiet=True):
        cmd = ['submodule', 'update', '--init', '--recursive']
        if quiet:
            cmd.append('-q')
        if GitCommand(self, cmd).Wait() != 0:
            raise GitError('%s submodule update --init --recursive %s ' % self.name)

    def _Rebase(self, upstream, onto=None):
        cmd = ['rebase']
        if onto is not None:
            cmd.extend(['--onto', onto])
        cmd.append(upstream)
        if GitCommand(self, cmd).Wait() != 0:
            raise GitError('%s rebase %s ' % (self.name, upstream))

    def _FastForward(self, head, ffonly=False):
        cmd = ['merge', '--no-stat', head]
        if ffonly:
            cmd.append("--ff-only")
        if GitCommand(self, cmd).Wait() != 0:
            raise GitError('%s merge %s ' % (self.name, head))

    def _InitGitDir(self, mirror_git=None, force_sync=False, quiet=False):
        init_git_dir = not os.path.exists(self.gitdir)
        init_obj_dir = not os.path.exists(self.objdir)
        try:
            # Initialize the bare repository, which contains all of the objects.
            if init_obj_dir:
                os.makedirs(self.objdir)
                self.bare_objdir.init()

                if self.use_git_worktrees:
                    # Set up the m/ space to point to the worktree-specific ref space.
                    # We'll update the worktree-specific ref space on each checkout.
                    if self.manifest.branch:
                        self.bare_git.symbolic_ref(
                            '-m', 'redirecting to worktree scope',
                            R_M + self.manifest.branch,
                            R_WORKTREE_M + self.manifest.branch)

                    # Enable per-worktree config file support if possible.  This is more a
                    # nice-to-have feature for users rather than a hard requirement.
                    if git_require((2, 20, 0)):
                        self.EnableRepositoryExtension('worktreeConfig')

            # If we have a separate directory to hold refs, initialize it as well.
            if self.objdir != self.gitdir:
                if init_git_dir:
                    os.makedirs(self.gitdir)

                if init_obj_dir or init_git_dir:
                    self._ReferenceGitDir(self.objdir, self.gitdir, share_refs=False,
                                          copy_all=True)
                try:
                    self._CheckDirReference(self.objdir, self.gitdir, share_refs=False)
                except GitError as e:
                    if force_sync:
                        print("Retrying clone after deleting %s" %
                              self.gitdir, file=sys.stderr)
                        try:
                            platform_utils.rmtree(platform_utils.realpath(self.gitdir))
                            if self.worktree and os.path.exists(platform_utils.realpath
                                                                    (self.worktree)):
                                platform_utils.rmtree(platform_utils.realpath(self.worktree))
                            return self._InitGitDir(mirror_git=mirror_git, force_sync=False,
                                                    quiet=quiet)
                        except Exception:
                            raise e
                    raise e

            if init_git_dir:
                mp = self.manifest.manifestProject
                ref_dir = mp.config.GetString('repo.reference') or ''

                if ref_dir or mirror_git:
                    if not mirror_git:
                        mirror_git = os.path.join(ref_dir, self.name + '.git')
                    repo_git = os.path.join(ref_dir, '.repo', 'projects',
                                            self.relpath + '.git')
                    worktrees_git = os.path.join(ref_dir, '.repo', 'worktrees',
                                                 self.name + '.git')

                    if os.path.exists(mirror_git):
                        ref_dir = mirror_git
                    elif os.path.exists(repo_git):
                        ref_dir = repo_git
                    elif os.path.exists(worktrees_git):
                        ref_dir = worktrees_git
                    else:
                        ref_dir = None

                    if ref_dir:
                        if not os.path.isabs(ref_dir):
                            # The alternate directory is relative to the object database.
                            ref_dir = os.path.relpath(ref_dir,
                                                      os.path.join(self.objdir, 'objects'))
                        _lwrite(os.path.join(self.gitdir, 'objects/info/alternates'),
                                os.path.join(ref_dir, 'objects') + '\n')

                self._UpdateHooks(quiet=quiet)

                m = self.manifest.manifestProject.config
                for key in ['user.name', 'user.email']:
                    if m.Has(key, include_defaults=False):
                        self.config.SetString(key, m.GetString(key))
                self.config.SetString('filter.lfs.smudge', 'git-lfs smudge --skip -- %f')
                self.config.SetString('filter.lfs.process', 'git-lfs filter-process --skip')
                if self.manifest.IsMirror:
                    self.config.SetString('core.bare', 'true')
                else:
                    self.config.SetString('core.bare', None)
        except Exception:
            if init_obj_dir and os.path.exists(self.objdir):
                platform_utils.rmtree(self.objdir)
            if init_git_dir and os.path.exists(self.gitdir):
                platform_utils.rmtree(self.gitdir)
            raise

    def _UpdateHooks(self, quiet=False):
        if os.path.exists(self.gitdir):
            self._InitHooks(quiet=quiet)

    def _InitHooks(self, quiet=False):
        hooks = platform_utils.realpath(self._gitdir_path('hooks'))
        if not os.path.exists(hooks):
            os.makedirs(hooks)
        for stock_hook in _ProjectHooks():
            name = os.path.basename(stock_hook)

            if name in ('commit-msg',) and not self.remote.review \
                    and self is not self.manifest.manifestProject:
                # Don't install a Gerrit Code Review hook if this
                # project does not appear to use it for reviews.
                #
                # Since the manifest project is one of those, but also
                # managed through gerrit, it's excluded
                continue

            dst = os.path.join(hooks, name)
            if platform_utils.islink(dst):
                continue
            if os.path.exists(dst):
                # If the files are the same, we'll leave it alone.  We create symlinks
                # below by default but fallback to hardlinks if the OS blocks them.
                # So if we're here, it's probably because we made a hardlink below.
                if not filecmp.cmp(stock_hook, dst, shallow=False):
                    if not quiet:
                        _warn("%s: Not replacing locally modified %s hook",
                              self.relpath, name)
                continue
            try:
                platform_utils.symlink(
                    os.path.relpath(stock_hook, os.path.dirname(dst)), dst)
            except OSError as e:
                if e.errno == errno.EPERM:
                    try:
                        os.link(stock_hook, dst)
                    except OSError:
                        raise GitError(self._get_symlink_error_message())
                else:
                    raise

    def _InitRemote(self):
        if self.remote.url:
            remote = self.GetRemote(self.remote.name)
            remote.url = self.remote.url
            remote.pushUrl = self.remote.pushUrl
            remote.review = self.remote.review
            remote.projectname = self.name

            if self.worktree:
                remote.ResetFetch(mirror=False)
            else:
                remote.ResetFetch(mirror=True)
            remote.Save()

    def _InitMRef(self):
        if self.manifest.branch:
            if self.use_git_worktrees:
                # We can't update this ref with git worktrees until it exists.
                # We'll wait until the initial checkout to set it.
                if not os.path.exists(self.worktree):
                    return

                base = R_WORKTREE_M
                active_git = self.work_git
            else:
                base = R_M
                active_git = self.bare_git

            self._InitAnyMRef(base + self.manifest.branch, active_git)

    def _InitMirrorHead(self):
        self._InitAnyMRef(HEAD, self.bare_git)

    def _InitAnyMRef(self, ref, active_git):
        cur = self.bare_ref.symref(ref)

        if self.revisionId:
            if cur != '' or self.bare_ref.get(ref) != self.revisionId:
                msg = 'manifest set to %s' % self.revisionId
                dst = self.revisionId + '^0'
                active_git.UpdateRef(ref, dst, message=msg, detach=True)
        else:
            remote = self.GetRemote(self.remote.name)
            dst = remote.ToLocal(self.revisionExpr)
            if cur != dst:
                msg = 'manifest set to %s' % self.revisionExpr
                active_git.symbolic_ref('-m', msg, ref, dst)

    def _CheckDirReference(self, srcdir, destdir, share_refs):
        # Git worktrees don't use symlinks to share at all.
        if self.use_git_worktrees:
            return

        symlink_files = self.shareable_files[:]
        symlink_dirs = self.shareable_dirs[:]
        if share_refs:
            symlink_files += self.working_tree_files
            symlink_dirs += self.working_tree_dirs
        to_symlink = symlink_files + symlink_dirs
        for name in set(to_symlink):
            # Try to self-heal a bit in simple cases.
            dst_path = os.path.join(destdir, name)
            src_path = os.path.join(srcdir, name)

            if name in self.working_tree_dirs:
                # If the dir is missing under .repo/projects/, create it.
                if not os.path.exists(src_path):
                    os.makedirs(src_path)

            elif name in self.working_tree_files:
                # If it's a file under the checkout .git/ and the .repo/projects/ has
                # nothing, move the file under the .repo/projects/ tree.
                if not os.path.exists(src_path) and os.path.isfile(dst_path):
                    platform_utils.rename(dst_path, src_path)

            # If the path exists under the .repo/projects/ and there's no symlink
            # under the checkout .git/, recreate the symlink.
            if name in self.working_tree_dirs or name in self.working_tree_files:
                if os.path.exists(src_path) and not os.path.exists(dst_path):
                    platform_utils.symlink(
                        os.path.relpath(src_path, os.path.dirname(dst_path)), dst_path)

            dst = platform_utils.realpath(dst_path)
            if os.path.lexists(dst):
                src = platform_utils.realpath(src_path)
                # Fail if the links are pointing to the wrong place
                if src != dst:
                    _error('%s is different in %s vs %s', name, destdir, srcdir)
                    raise GitError('--force-sync not enabled; cannot overwrite a local '
                                   'work tree. If you\'re comfortable with the '
                                   'possibility of losing the work tree\'s git metadata,'
                                   ' use `repo sync --force-sync {0}` to '
                                   'proceed.'.format(self.relpath))

    def _ReferenceGitDir(self, gitdir, dotgit, share_refs, copy_all):
        """Update |dotgit| to reference |gitdir|, using symlinks where possible.

        Args:
          gitdir: The bare git repository. Must already be initialized.
          dotgit: The repository you would like to initialize.
          share_refs: If true, |dotgit| will store its refs under |gitdir|.
              Only one work tree can store refs under a given |gitdir|.
          copy_all: If true, copy all remaining files from |gitdir| -> |dotgit|.
              This saves you the effort of initializing |dotgit| yourself.
        """
        symlink_files = self.shareable_files[:]
        symlink_dirs = self.shareable_dirs[:]
        if share_refs:
            symlink_files += self.working_tree_files
            symlink_dirs += self.working_tree_dirs
        to_symlink = symlink_files + symlink_dirs

        to_copy = []
        if copy_all:
            to_copy = platform_utils.listdir(gitdir)

        dotgit = platform_utils.realpath(dotgit)
        for name in set(to_copy).union(to_symlink):
            try:
                src = platform_utils.realpath(os.path.join(gitdir, name))
                dst = os.path.join(dotgit, name)

                if os.path.lexists(dst):
                    continue

                # If the source dir doesn't exist, create an empty dir.
                if name in symlink_dirs and not os.path.lexists(src):
                    os.makedirs(src)

                if name in to_symlink:
                    platform_utils.symlink(
                        os.path.relpath(src, os.path.dirname(dst)), dst)
                elif copy_all and not platform_utils.islink(dst):
                    if platform_utils.isdir(src):
                        shutil.copytree(src, dst)
                    elif os.path.isfile(src):
                        shutil.copy(src, dst)

                # If the source file doesn't exist, ensure the destination
                # file doesn't either.
                if name in symlink_files and not os.path.lexists(src):
                    try:
                        platform_utils.remove(dst)
                    except OSError:
                        pass

            except OSError as e:
                if e.errno == errno.EPERM:
                    raise DownloadError(self._get_symlink_error_message())
                else:
                    raise

    def _InitGitWorktree(self):
        """Init the project using git worktrees."""
        self.bare_git.worktree('prune')
        self.bare_git.worktree('add', '-ff', '--checkout', '--detach', '--lock',
                               self.worktree, self.GetRevisionId())

        # Rewrite the internal state files to use relative paths between the
        # checkouts & worktrees.
        dotgit = os.path.join(self.worktree, '.git')
        with open(dotgit, 'r') as fp:
            # Figure out the checkout->worktree path.
            setting = fp.read()
            assert setting.startswith('gitdir:')
            git_worktree_path = setting.split(':', 1)[1].strip()
        # Some platforms (e.g. Windows) won't let us update dotgit in situ because
        # of file permissions.  Delete it and recreate it from scratch to avoid.
        platform_utils.remove(dotgit)
        # Use relative path from checkout->worktree.
        with open(dotgit, 'w') as fp:
            print('gitdir:', os.path.relpath(git_worktree_path, self.worktree),
                  file=fp)
        # Use relative path from worktree->checkout.
        with open(os.path.join(git_worktree_path, 'gitdir'), 'w') as fp:
            print(os.path.relpath(dotgit, git_worktree_path), file=fp)

        self._InitMRef()

    def _InitWorkTree(self, force_sync=False, submodules=False):
        realdotgit = os.path.join(self.worktree, '.git')
        tmpdotgit = realdotgit + '.tmp'
        init_dotgit = not os.path.exists(realdotgit)
        if init_dotgit:
            if self.use_git_worktrees:
                self._InitGitWorktree()
                self._CopyAndLinkFiles()
                return

            dotgit = tmpdotgit
            platform_utils.rmtree(tmpdotgit, ignore_errors=True)
            os.makedirs(tmpdotgit)
            self._ReferenceGitDir(self.gitdir, tmpdotgit, share_refs=True,
                                  copy_all=False)
        else:
            dotgit = realdotgit

        try:
            self._CheckDirReference(self.gitdir, dotgit, share_refs=True)
        except GitError as e:
            if force_sync and not init_dotgit:
                try:
                    platform_utils.rmtree(dotgit)
                    return self._InitWorkTree(force_sync=False, submodules=submodules)
                except Exception:
                    raise e
            raise e

        if init_dotgit:
            _lwrite(os.path.join(tmpdotgit, HEAD), '%s\n' % self.GetRevisionId())

            # Now that the .git dir is fully set up, move it to its final home.
            platform_utils.rename(tmpdotgit, realdotgit)

            # Finish checking out the worktree.
            cmd = ['read-tree', '--reset', '-u']
            cmd.append('-v')
            cmd.append(HEAD)
            if GitCommand(self, cmd).Wait() != 0:
                raise GitError('Cannot initialize work tree for ' + self.name)

            if submodules:
                self._SyncSubmodules(quiet=True)
            self._CopyAndLinkFiles()

    def _get_symlink_error_message(self):
        if platform_utils.isWindows():
            return ('Unable to create symbolic link. Please re-run the command as '
                    'Administrator, or see '
                    'https://github.com/git-for-windows/git/wiki/Symbolic-Links '
                    'for other options.')
        return 'filesystem must support symlinks'

    def _gitdir_path(self, path):
        return platform_utils.realpath(os.path.join(self.gitdir, path))

    def _revlist(self, *args, **kw):
        a = []
        a.extend(args)
        a.append('--')
        return self.work_git.rev_list(*a, **kw)

    @property
    def _allrefs(self):
        return self.bare_ref.all

    def _getLogs(self, rev1, rev2, oneline=False, color=True, pretty_format=None):
        """Get logs between two revisions of this project."""
        comp = '..'
        if rev1:
            revs = [rev1]
            if rev2:
                revs.extend([comp, rev2])
            cmd = ['log', ''.join(revs)]
            out = DiffColoring(self.config)
            if out.is_on and color:
                cmd.append('--color')
            if pretty_format is not None:
                cmd.append('--pretty=format:%s' % pretty_format)
            if oneline:
                cmd.append('--oneline')

            try:
                log = GitCommand(self, cmd, capture_stdout=True, capture_stderr=True)
                if log.Wait() == 0:
                    return log.stdout
            except GitError:
                # worktree may not exist if groups changed for example. In that case,
                # try in gitdir instead.
                if not os.path.exists(self.worktree):
                    return self.bare_git.log(*cmd[1:])
                else:
                    raise
        return None

    def getAddedAndRemovedLogs(self, toProject, oneline=False, color=True,
                               pretty_format=None):
        """Get the list of logs from this revision to given revisionId"""
        logs = {}
        selfId = self.GetRevisionId(self._allrefs)
        toId = toProject.GetRevisionId(toProject._allrefs)

        logs['added'] = self._getLogs(selfId, toId, oneline=oneline, color=color,
                                      pretty_format=pretty_format)
        logs['removed'] = self._getLogs(toId, selfId, oneline=oneline, color=color,
                                        pretty_format=pretty_format)
        return logs

    class _GitGetByExec(object):

        def __init__(self, project, bare, gitdir):
            self._project = project
            self._bare = bare
            self._gitdir = gitdir

        def LsOthers(self):
            p = GitCommand(self._project,
                           ['ls-files',
                            '-z',
                            '--others',
                            '--exclude-standard'],
                           bare=False,
                           gitdir=self._gitdir,
                           capture_stdout=True,
                           capture_stderr=True)
            if p.Wait() == 0:
                out = p.stdout
                if out:
                    # Backslash is not anomalous
                    return out[:-1].split('\0')
            return []

        def DiffZ(self, name, *args):
            cmd = [name]
            cmd.append('-z')
            cmd.append('--ignore-submodules')
            cmd.extend(args)
            p = GitCommand(self._project,
                           cmd,
                           gitdir=self._gitdir,
                           bare=False,
                           capture_stdout=True,
                           capture_stderr=True)
            try:
                out = p.process.stdout.read()
                if not hasattr(out, 'encode'):
                    out = out.decode()
                r = {}
                if out:
                    out = iter(out[:-1].split('\0'))
                    while out:
                        try:
                            info = next(out)
                            path = next(out)
                        except StopIteration:
                            break

                        class _Info(object):

                            def __init__(self, path, omode, nmode, oid, nid, state):
                                self.path = path
                                self.src_path = None
                                self.old_mode = omode
                                self.new_mode = nmode
                                self.old_id = oid
                                self.new_id = nid

                                if len(state) == 1:
                                    self.status = state
                                    self.level = None
                                else:
                                    self.status = state[:1]
                                    self.level = state[1:]
                                    while self.level.startswith('0'):
                                        self.level = self.level[1:]

                        info = info[1:].split(' ')
                        info = _Info(path, *info)
                        if info.status in ('R', 'C'):
                            info.src_path = info.path
                            info.path = next(out)
                        r[info.path] = info
                return r
            finally:
                p.Wait()

        def GetDotgitPath(self, subpath=None):
            """Return the full path to the .git dir.

            As a convenience, append |subpath| if provided.
            """
            if self._bare:
                dotgit = self._gitdir
            else:
                dotgit = os.path.join(self._project.worktree, '.git')
                if os.path.isfile(dotgit):
                    # Git worktrees use a "gitdir:" syntax to point to the scratch space.
                    with open(dotgit) as fp:
                        setting = fp.read()
                    assert setting.startswith('gitdir:')
                    gitdir = setting.split(':', 1)[1].strip()
                    dotgit = os.path.normpath(os.path.join(self._project.worktree, gitdir))

            return dotgit if subpath is None else os.path.join(dotgit, subpath)

        def GetHead(self):
            """Return the ref that HEAD points to."""
            path = self.GetDotgitPath(subpath=HEAD)
            try:
                with open(path) as fd:
                    line = fd.readline()
            except IOError as e:
                raise NoManifestException(path, str(e))
            try:
                line = line.decode()
            except AttributeError:
                pass
            if line.startswith('ref: '):
                return line[5:-1]
            return line[:-1]

        def SetHead(self, ref, message=None):
            cmdv = []
            if message is not None:
                cmdv.extend(['-m', message])
            cmdv.append(HEAD)
            cmdv.append(ref)
            self.symbolic_ref(*cmdv)

        def DetachHead(self, new, message=None):
            cmdv = ['--no-deref']
            if message is not None:
                cmdv.extend(['-m', message])
            cmdv.append(HEAD)
            cmdv.append(new)
            self.update_ref(*cmdv)

        def UpdateRef(self, name, new, old=None,
                      message=None,
                      detach=False):
            cmdv = []
            if message is not None:
                cmdv.extend(['-m', message])
            if detach:
                cmdv.append('--no-deref')
            cmdv.append(name)
            cmdv.append(new)
            if old is not None:
                cmdv.append(old)
            self.update_ref(*cmdv)

        def DeleteRef(self, name, old=None):
            if not old:
                old = self.rev_parse(name)
            self.update_ref('-d', name, old)
            self._project.bare_ref.deleted(name)

        def rev_list(self, *args, **kw):
            if 'format' in kw:
                cmdv = ['log', '--pretty=format:%s' % kw['format']]
            else:
                cmdv = ['rev-list']
            cmdv.extend(args)
            p = GitCommand(self._project,
                           cmdv,
                           bare=self._bare,
                           gitdir=self._gitdir,
                           capture_stdout=True,
                           capture_stderr=True)
            if p.Wait() != 0:
                raise GitError('%s rev-list %s: %s' %
                               (self._project.name, str(args), p.stderr))
            return p.stdout.splitlines()

        def __getattr__(self, name):
            """Allow arbitrary git commands using pythonic syntax.

            This allows you to do things like:
              git_obj.rev_parse('HEAD')

            Since we don't have a 'rev_parse' method defined, the __getattr__ will
            run.  We'll replace the '_' with a '-' and try to run a git command.
            Any other positional arguments will be passed to the git command, and the
            following keyword arguments are supported:
              config: An optional dict of git config options to be passed with '-c'.

            Args:
              name: The name of the git command to call.  Any '_' characters will
                  be replaced with '-'.

            Returns:
              A callable object that will try to call git with the named command.
            """
            name = name.replace('_', '-')

            def runner(*args, **kwargs):
                cmdv = []
                config = kwargs.pop('config', None)
                for k in kwargs:
                    raise TypeError('%s() got an unexpected keyword argument %r'
                                    % (name, k))
                if config is not None:
                    for k, v in config.items():
                        cmdv.append('-c')
                        cmdv.append('%s=%s' % (k, v))
                cmdv.append(name)
                cmdv.extend(args)
                p = GitCommand(self._project,
                               cmdv,
                               bare=self._bare,
                               gitdir=self._gitdir,
                               capture_stdout=True,
                               capture_stderr=True)
                if p.Wait() != 0:
                    raise GitError('%s %s: %s' %
                                   (self._project.name, name, p.stderr))
                r = p.stdout
                if r.endswith('\n') and r.index('\n') == len(r) - 1:
                    return r[:-1]
                return r
            return runner


class _PriorSyncFailedError(Exception):

    def __str__(self):
        return 'prior sync failed; rebase still in progress'


class _DirtyError(Exception):

    def __str__(self):
        return 'contains uncommitted changes'


class _InfoMessage(object):

    def __init__(self, project, text):
        self.project = project
        self.text = text

    def Print(self, syncbuf):
        syncbuf.out.info('%s/: %s', self.project.relpath, self.text)
        syncbuf.out.nl()


class _Failure(object):

    def __init__(self, project, why):
        self.project = project
        self.why = why

    def Print(self, syncbuf):
        syncbuf.out.fail('error: %s/: %s',
                         self.project.relpath,
                         str(self.why))
        syncbuf.out.nl()


class _Later(object):

    def __init__(self, project, action):
        self.project = project
        self.action = action

    def Run(self, syncbuf):
        out = syncbuf.out
        out.project('project %s/', self.project.relpath)
        out.nl()
        try:
            self.action()
            out.nl()
            return True
        except GitError:
            out.nl()
            return False


class _SyncColoring(Coloring):

    def __init__(self, config):
        Coloring.__init__(self, config, 'reposync')
        self.project = self.printer('header', attr='bold')
        self.info = self.printer('info')
        self.fail = self.printer('fail', fg='red')


class SyncBuffer(object):

    def __init__(self, config, detach_head=False):
        self._messages = []
        self._failures = []
        self._later_queue1 = []
        self._later_queue2 = []

        self.out = _SyncColoring(config)
        self.out.redirect(sys.stderr)

        self.detach_head = detach_head
        self.clean = True
        self.recent_clean = True

    def info(self, project, fmt, *args):
        self._messages.append(_InfoMessage(project, fmt % args))

    def fail(self, project, err=None):
        self._failures.append(_Failure(project, err))
        self._MarkUnclean()

    def later1(self, project, what):
        self._later_queue1.append(_Later(project, what))

    def later2(self, project, what):
        self._later_queue2.append(_Later(project, what))

    def Finish(self):
        self._PrintMessages()
        self._RunLater()
        self._PrintMessages()
        return self.clean

    def Recently(self):
        recent_clean = self.recent_clean
        self.recent_clean = True
        return recent_clean

    def _MarkUnclean(self):
        self.clean = False
        self.recent_clean = False

    def _RunLater(self):
        for q in ['_later_queue1', '_later_queue2']:
            if not self._RunQueue(q):
                return

    def _RunQueue(self, queue):
        for m in getattr(self, queue):
            if not m.Run(self):
                self._MarkUnclean()
                return False
        setattr(self, queue, [])
        return True

    def _PrintMessages(self):
        if self._messages or self._failures:
            if os.isatty(2):
                self.out.write(progress.CSI_ERASE_LINE)
            self.out.write('\r')

        for m in self._messages:
            m.Print(self)
        for m in self._failures:
            m.Print(self)

        self._messages = []
        self._failures = []


class MetaProject(Project):

    """A special project housed under .repo.
    """

    def __init__(self, manifest, name, gitdir, worktree):
        Project.__init__(self,
                         manifest=manifest,
                         name=name,
                         gitdir=gitdir,
                         objdir=gitdir,
                         worktree=worktree,
                         remote=RemoteSpec('origin'),
                         relpath='.repo/%s' % name,
                         revisionExpr='refs/heads/master',
                         revisionId=None,
                         groups=None)

    def PreSync(self):
        if self.Exists:
            cb = self.CurrentBranch
            if cb:
                base = self.GetBranch(cb).merge
                if base:
                    self.revisionExpr = base
                    self.revisionId = None

    def MetaBranchSwitch(self, submodules=False):
        """ Prepare MetaProject for manifest branch switch
        """

        # detach and delete manifest branch, allowing a new
        # branch to take over
        syncbuf = SyncBuffer(self.config, detach_head=True)
        self.Sync_LocalHalf(syncbuf, submodules=submodules)
        syncbuf.Finish()

        return GitCommand(self,
                          ['update-ref', '-d', 'refs/heads/default'],
                          capture_stdout=True,
                          capture_stderr=True).Wait() == 0

    @property
    def LastFetch(self):
        try:
            fh = os.path.join(self.gitdir, 'FETCH_HEAD')
            return os.path.getmtime(fh)
        except OSError:
            return 0

    @property
    def HasChanges(self):
        """Has the remote received new commits not yet checked out?
        """
        if not self.remote or not self.revisionExpr:
            return False

        all_refs = self.bare_ref.all
        revid = self.GetRevisionId(all_refs)
        head = self.work_git.GetHead()
        if head.startswith(R_HEADS):
            try:
                head = all_refs[head]
            except KeyError:
                head = None

        if revid == head:
            return False
        elif self._revlist(not_rev(HEAD), revid):
            return True
        return False
